Energy storage devices such as batteries hold great importance for society, owing to their high e... more Energy storage devices such as batteries hold great importance for society, owing to their high energy density, environmental benignity and low cost. However, critical issues related to their performance and safety still need to be resolved. The periodic table of elements is pivotal to chemistry, physics, biology and engineering and represents a remarkable scientific breakthrough that sheds light on the fundamental laws of nature. Here, we provide an overview of the role of the most prominent elements, including s-block, p-block, transition and inner-transition metals, as electrode materials for lithium-ion battery systems regarding their perspective applications and fundamental properties. We also outline hybrid materials, such as MXenes, transition metal oxides, alloys and graphene oxide. Finally, the challenges and prospects of each element and their derivatives and hybrids for future battery systems are discussed, which may provide guidance towards green, low-cost, versatile and...
R factor = 0.051; wR factor = 0.158; data-to-parameter ratio = 15.0. In the title compound, C19H2... more R factor = 0.051; wR factor = 0.158; data-to-parameter ratio = 15.0. In the title compound, C19H25NO2, the 3-ethoxy-2-hydroxy-benzaldehyde group is almost planar (r.m.s. deviation = 0.029 Å). An intramolecular O—H N hydrogen bond generates an S(6) ring. There are no intermolecular hydrogen bonds.
In this study, soybean straw (SS) as a promising source of glycolaldehyde-rich bio-oil production... more In this study, soybean straw (SS) as a promising source of glycolaldehyde-rich bio-oil production and extraction was investigated. Proximate and ultimate analysis of SS was performed to examine the feasibility and suitability of SS for thermochemical conversion design. The effect of the co-catalyst (CaCl 2 + ash) on glycolaldehyde concentration (%) was examined. Thermogravimetric-Fourier-transform infrared (TG-FTIR) analysis was applied to optimize the pyrolysis temperature and biomass-to-catalyst ratio for glycolaldehyde-rich bio-oil production. By TG-FTIR analysis, the highest glycolaldehyde concentration of 8.57% was obtained at 500°C without the catalyst, while 12.76 and 13.56% were obtained with the catalyst at 500°C for a 1:6 ratio of SS-to-CaCl 2 and a 1:4 ratio of SSto-ash, respectively. Meanwhile, the highest glycolaldehyde concentrations (%) determined by gas chromatography−mass spectrometry (GC−MS) analysis for bio-oils produced at 500°C (without the catalyst), a 1:6 ratio of SS-to-CaCl 2 , and a 1:4 ratio of SS-to-ash were found to be 11.3, 17.1, and 16.8%, respectively. These outcomes were fully consistent with the TG-FTIR results. Moreover, the effect of temperature on product distribution was investigated, and the highest bio-oil yield was achieved at 500°C as 56.1%. This research work aims to develop an environmentfriendly extraction technique involving aqueous-based imitation for glycolaldehyde extraction with 23.6% yield. Meanwhile, proton nuclear magnetic resonance (1 H NMR) analysis was used to confirm the purity of the extracted glycolaldehyde, which was found as 91%.
The inexpensive Co3C proved itself as highly efficient cocatalyst to generate economical H2. An a... more The inexpensive Co3C proved itself as highly efficient cocatalyst to generate economical H2. An apparent quantum yield of 19% was achieved which is among the best reported carbide-based cocatalysts.
Abstract Highly efficient Ag-doped ZnO (Ag-ZnO)/sulfurized graphitic C3N4 heterostructure photoca... more Abstract Highly efficient Ag-doped ZnO (Ag-ZnO)/sulfurized graphitic C3N4 heterostructure photocatalyst was synthesized in a two-step hydrothermal route. Initially, Ag (1–9%) was doped into ZnO nanostructure and checked photocatalytic properties. 7% Ag-doped ZnO (7Ag-ZnO) NPs shown best photocatalytic methylene blue (MB) dye degradation under visible radiation, so, it was selected for forming composite with S-g-C3N4. In 1st step, S-g-C3N4 was synthesized by calcinating. In the 2nd step, 7Ag-ZnO/S-g-C3N4 heterostructure photocatalyst was formed by in situ formation of 7Ag-ZnO NPs in the presence of different contents of S-g-C3N4 (3.5–75 wt%) through hydrothermal route. As a result of 7Ag-ZnO/S-g-C3N4 heterostructure, a large number of catalytic active sites were generated for photocatalytic degradation. Interestingly, the 7% Ag-ZnO nanoparticles (NPs) with 25% S-g-C3N4 exhibited 97% MB degraded within 40 min, which was degraded up to 57% by 7Ag-ZnO alone. Moreover, the photo corrosion of ZnO NPs was inhibited by doping with Ag and coupling with S-g-C3N4.
Abstract Fast pyrolysis has appeared as a promising technology for bio-fuels and bio-based chemic... more Abstract Fast pyrolysis has appeared as a promising technology for bio-fuels and bio-based chemicals production. This paper reports tea waste (TW) as a promising source of phenolic-rich bio-oil production via catalytic fast pyrolysis in fluidized bed reactor. TG-FTIR analysis is applied to optimize pyrolysis temperature for phenolic-rich bio-oil production and maximum phenols yield (17.3 %) was obtained at 500 °C. Meanwhile, bio-oils are produced at each corresponding temperatures of TG-FTIR analysis and GC–MS analysis is performed to examine consistency and authenticity of TG-FTIR results. Moreover, catalytic effect of activated carbon + KOH (AC-K) with different biomass-to-catalyst ratio was examined to optimize most efficient ratio at 500 °C and maximum phenol contents (39.72 %) were obtained at 1:6 ratio of biomass-to-catalyst as compared to non-catalytic pyrolysis (23.85 %). Moreover, effect of temperature on product distribution was examined and maximum liquid yield (40.7 %) was obtained at 500 °C. Furthermore, switchable hydrophilic solvents (SHS) were used to isolate phenols from bio-oil with 95.02 % yield calculated by GC–MS analysis. The elemental analysis and high heating value (HHV) of the crude and residue bio-oil were determined. The carbon contents and HHV of residue bio-oil were increased to 67.3 % and 13.7 MJ/Kg from 46.2 % and 10.38 MJ/Kg respectively while; oxygen contents were decreased to 19.7 from 45.3 % demonstrating its potential for fuel application.
Abstract The development of cheap and effective catalysts is one of the major challenges to boost... more Abstract The development of cheap and effective catalysts is one of the major challenges to boost up electrocatalytic oxygen evolution reaction (OER). In this study, we synthesized phosphorus incorporated nickel sulfide (Ni3S2@Ni5P4/NF) composite via a simple one-step hydrothermal treatment for electrocatalytic oxygen evolution reaction in basic media. The newly synthesized Ni3S2@Ni5P4/NF composite catalyst shows a remarkable OER activity with an overpotential of 399 mV at a current density of 50 mA cm-2. Ni3S2@Ni5P4/NF also shows a Tafel slope of 75 mV dec-1 with long-term stability for more than 15 hours in alkaline media. The enhanced electrocatalytic activity of current system is among best catalysts based on Nickle sulfides and nickel phosphides according to our knowledge. Current enhancement can be attributed to fast electron transfer due to synergistic effect of Ni3S2 and Ni5P4 in the composite.
Critical role of the heterojunction interface of silver decorated ZnO nanocomposite with sulfuriz... more Critical role of the heterojunction interface of silver decorated ZnO nanocomposite with sulfurized graphitic carbon nitride heterostructure materials for photocatalytic a p p l i c a t i o ns ,
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
The catalytic decomposition of formic acid to generate syngas (a mixture of H2 and CO) is a highl... more The catalytic decomposition of formic acid to generate syngas (a mixture of H2 and CO) is a highly valuable strategy for energy conversion. Syngas can be used directly in internal combustion engines or can be converted to liquid fuels, meeting future energy challenges in a sustainable manner. Herein, we report the use of homogeneous molecular iron catalysts combined with a CdS nanorods (NRs) semiconductor to construct a highly efficient photocatalytic system for direct conversion of formic acid to syngas at room temperature and atmospheric pressure. Under optimal conditions, the photocatalytic system presents an activity of 150 mmol gcatalyst-1 h-1 towards H2 , and an apparent quantum yield (AQY) of 16.8 %, making it among the most active noble-metal-free photocatalytic systems for H2 evolution from formic acid under visible light. Meanwhile, these iron-based molecular catalysts also demonstrate remarkable enhancement in CO evolution with robust stability. The mechanistic role of the molecular catalyst is further investigated by using cyclic voltammetry, which suggests the formation of FeI species as the key step in the catalytic conversion of formic acid to syngas.
Two dimensional (2D) nanomaterials have interesting properties due to their lateral dimensions. P... more Two dimensional (2D) nanomaterials have interesting properties due to their lateral dimensions. Pure self-assembled L-cysteine stabilized covellite nanoplates (CuS@L-Cys NPs) and L-cysteine stabilized chalcocite nano leaves (Cu 2 S@L-Cys NLs) were synthesized by using a template free, the facile hydrothermal route with the best control of size, phase purity structure, morphology, and electrochemical properties. Novel CuS@L-Cys NPs and Cu 2 S@L-Cys NLs snowflakes dendrites were synthesized by varying synthetic parameters such as solvent, temperature (100-180°C), reaction time (8-24 h), pH of reaction medium (7-14), the concentration of base (0.1-2.4 mL NH 3) and concentration of thiourea (1-4 mmol). By changing these factors, different morphologies such as irregular, regular, trigonal, hexagonal leaf and snowflakes dendrites like shapes were observed.
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2020
Abstract Template-free, the facile hydrothermal route was used for the synthesis of pure self-ass... more Abstract Template-free, the facile hydrothermal route was used for the synthesis of pure self-assembled l -cysteine stabilized chalcocite nanoleaves (Cu2S@L-Cys NLs) with the best control of size, phase purity structure, morphology, and electrochemical properties. Effect of temperature (100–180 °C) and reaction time (8−24 h) were studied on the morphology of chalcocite Cu2S@L-Cys NLs snowflakes dendrites. By changing these factors, different morphologies such as irregular, regular, trigonal, hexagonal nanoleaf, and snowflakes dendrites like shapes were observed. Cu2S@L-Cys NLs were fabricated by using ethylenediamine (EDA) as a solvent. The photocatalytic performances of as-prepared Cu2S@L-Cys snowflake dendrites (NL3) and Cu2S@L-Cys irregular hexagram (NL4) in the degradation of methyl orange (MO) were examined under visible light. The noteworthy, unique bandgap (Cu2S@L-Cys snowflake dendrites NLs (1.55 eV) and Cu2S@L-Cys irregular hexagram NLs (1.58 eV) and the special morphology of Cu2S@L-Cys NLs increases the active sites for adsorption of dye, which causes extraordinary degradation activity. Furthermore, the l -cysteine (L-Cys) protective layer could efficiently alleviate the photocorrosion of Cu2S, giving rise to excellent stability. Cu2S@L-Cys NLs were reused successfully for photodegradation of dye due to the recycling ability of Cu2S@L-Cys NLs. The Cu2S@L-Cys snowflake dendrites NLs showed improved photocatalytic activity as compared to Cu2S@L-Cys irregular hexagram NLs. The improved surface area of Cu2S@L-Cys snowflake dendrites NLs, compared to that of the Cu2S@L-Cys irregular hexagram NLs, may be ascribed to the fact that snowflakes dendrites can support the growth and more surface-active sites of Cu2S@L-Cys. These results strongly suggest that the Cu2S@L-Cys snowflake dendrites are promising candidates for photocatalytic dye degradation.
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
A contrapositionally substituted derivative of cyclohexa-meta-phenylene ([6]CMP) was synthesized ... more A contrapositionally substituted derivative of cyclohexa-meta-phenylene ([6]CMP) was synthesized by an intramolecular Yamamoto coupling reaction of an appropriate terphenyl unit containing a trimethylsilyl substituent. Iododesilylation of the trimethylsilyl groups of the product with iodine monochloride was used to incorporate iodo groups, an important functionality for metal-catalyzed coupling reactions. The iodo groups were also converted into a (pinacolato)boryl groups, another important functionality for coupling reactions. The diborylated [6]CMP is expected to be a versatile potential comonomer and a precursor for the synthesis of CMP-based materials. The synthetic route to the disubstituted [6]CMP included lithiation, Pd-catalyzed borylation, Suzuki coupling, and Yamamoto coupling. The structure of the product was established by NMR spectroscopy and mass spectrometry.
The aims of this study is to investigate the effects of functional groups like eC]Ce and CeOH on ... more The aims of this study is to investigate the effects of functional groups like eC]Ce and CeOH on variation of higher heating values (HHV) of organic compounds. HHV of fuel hydrocarbons, gaseous and liquids including single bonded and multiple bonded carbons and green tea polyphenols (GTP) were determined by using Bomb Calorimeter. It was observed that, multiple bonded carbon and oxygen bonded carbon i.e. eC]Ce and eCeOe result in less carbon reduced state while, also increase endothermicity of reactants by changing hybridization state with more s-character and hence, contribute to lower level of HHV. Besides, hydrogen bonding was also considered as the major cause of the difference in HHV of fuel hydrocarbons having the same molecular formula but different oxygen-bearing functional groups due to structure stabilization. These statements were further supported by the combination of Fourier transform infra-red spectra (FTIR) and HHV calculation of raw GTP (set as a representative of biomass) and its solid products obtained at 250°C and 350°C by thermal treatment done by using high temperature tube furnace.
Photocatalytic hydrogen (H2) evolution is a promising approach for future sustainable energy util... more Photocatalytic hydrogen (H2) evolution is a promising approach for future sustainable energy utilization. However, it is still a great challenge to develop efficient and stable metal-free photocatalysts with broadband solar absorption in the visible region for H2 production. Metal-free graphene quantum dot (GQD) is an emerging candidate for this purpose because of its good water-solubility and tunable band gap. On the other hand, metal phosphides (Ni2P, Co2P, etc) have been demonstrated as novel noble-metal-free cocatalysts for water splitting, which can efficiently separate electron-hole pairs and enhance the photocatalytic activities. Herein, we report for the first time on the use of OH-functionalized GQDs (OH-GQDs) photosensitizer coupled with Ni2P nanoparticles for photocatalytic H2 production with λ > 420 nm light. The H2 production rate is ~94 times higher than that of bare OH-GQDs, which is even comparable to that of OH-GQDs with 1.0 wt% Pt cocatalyst. This enhancement is probably due to the semiconductor-cocatalyst interface interaction between Ni2P and OH-GQDs to facilitate efficient charge transfer process.
Noble-metal-free cobalt nitride (Co3N) can be used as a novel cocatalyst on CdS nanorods for phot... more Noble-metal-free cobalt nitride (Co3N) can be used as a novel cocatalyst on CdS nanorods for photocatalytic H2production in water under visible light irradiation.
Photocatalytic production of hydrogen by water splitting is a promising pathway for the conversio... more Photocatalytic production of hydrogen by water splitting is a promising pathway for the conversion of solar energy into chemical energy. However, the photocatalytic conversion efficiency is often limited by the sluggish transfer of the photogenerated charge carriers, charge recombination, and subsequent slow catalytic reactions. Herein, we report a highly active noble-metal-free photocatalytic system for hydrogen production in water. The system contains a water-soluble nickel complex as a molecular cocatalyst and zinc sulfide on 1D cadmium sulfide as the heterojunction photocatalyst. The complex can efficiently transport photogenerated electrons and holes over a heterojunction photocatalyst to hamper charge recombination, leading to highly improved catalytic efficiency and durability of a heterojunction photocatalyst- molecular cocatalyst system. The results show that under optimal conditions, the average apparent quantum yield was approximately 58.3 % after 7 h of irradiation with ...
Dalton transactions (Cambridge, England : 2003), Jan 9, 2016
Photocatalytic hydrogen production via water splitting has attracted much attention for future cl... more Photocatalytic hydrogen production via water splitting has attracted much attention for future clean energy application. Herein we report a noble-metal-free photocatalytic hydrogen production system containing a simple bidentate cobalt Schiff base complex as the molecular cocatalyst, CdS nanorods as the photosensitizer, and ascorbic acid as the electron donor. The system shows highly enhanced photocatalytic activity compared to pure CdS NRs under visible light (λ > 420 nm). Under optimal conditions, the turnover numbers (TONs) for hydrogen production reached ∼15 200 after 12 hours of irradiation, and an apparent quantum yield of ∼27% was achieved at 420 nm monochromatic light. Steady-state photoluminescence (PL) spectra indicated efficient charge transfer between the excited CdS NRs and the cobalt cocatalyst for improved hydrogen production. Spectroscopic studies of the photocatalytic reaction revealed the reduction of the Co(ii) complex to Co(i) species, which are probably activ...
Energy storage devices such as batteries hold great importance for society, owing to their high e... more Energy storage devices such as batteries hold great importance for society, owing to their high energy density, environmental benignity and low cost. However, critical issues related to their performance and safety still need to be resolved. The periodic table of elements is pivotal to chemistry, physics, biology and engineering and represents a remarkable scientific breakthrough that sheds light on the fundamental laws of nature. Here, we provide an overview of the role of the most prominent elements, including s-block, p-block, transition and inner-transition metals, as electrode materials for lithium-ion battery systems regarding their perspective applications and fundamental properties. We also outline hybrid materials, such as MXenes, transition metal oxides, alloys and graphene oxide. Finally, the challenges and prospects of each element and their derivatives and hybrids for future battery systems are discussed, which may provide guidance towards green, low-cost, versatile and...
R factor = 0.051; wR factor = 0.158; data-to-parameter ratio = 15.0. In the title compound, C19H2... more R factor = 0.051; wR factor = 0.158; data-to-parameter ratio = 15.0. In the title compound, C19H25NO2, the 3-ethoxy-2-hydroxy-benzaldehyde group is almost planar (r.m.s. deviation = 0.029 Å). An intramolecular O—H N hydrogen bond generates an S(6) ring. There are no intermolecular hydrogen bonds.
In this study, soybean straw (SS) as a promising source of glycolaldehyde-rich bio-oil production... more In this study, soybean straw (SS) as a promising source of glycolaldehyde-rich bio-oil production and extraction was investigated. Proximate and ultimate analysis of SS was performed to examine the feasibility and suitability of SS for thermochemical conversion design. The effect of the co-catalyst (CaCl 2 + ash) on glycolaldehyde concentration (%) was examined. Thermogravimetric-Fourier-transform infrared (TG-FTIR) analysis was applied to optimize the pyrolysis temperature and biomass-to-catalyst ratio for glycolaldehyde-rich bio-oil production. By TG-FTIR analysis, the highest glycolaldehyde concentration of 8.57% was obtained at 500°C without the catalyst, while 12.76 and 13.56% were obtained with the catalyst at 500°C for a 1:6 ratio of SS-to-CaCl 2 and a 1:4 ratio of SSto-ash, respectively. Meanwhile, the highest glycolaldehyde concentrations (%) determined by gas chromatography−mass spectrometry (GC−MS) analysis for bio-oils produced at 500°C (without the catalyst), a 1:6 ratio of SS-to-CaCl 2 , and a 1:4 ratio of SS-to-ash were found to be 11.3, 17.1, and 16.8%, respectively. These outcomes were fully consistent with the TG-FTIR results. Moreover, the effect of temperature on product distribution was investigated, and the highest bio-oil yield was achieved at 500°C as 56.1%. This research work aims to develop an environmentfriendly extraction technique involving aqueous-based imitation for glycolaldehyde extraction with 23.6% yield. Meanwhile, proton nuclear magnetic resonance (1 H NMR) analysis was used to confirm the purity of the extracted glycolaldehyde, which was found as 91%.
The inexpensive Co3C proved itself as highly efficient cocatalyst to generate economical H2. An a... more The inexpensive Co3C proved itself as highly efficient cocatalyst to generate economical H2. An apparent quantum yield of 19% was achieved which is among the best reported carbide-based cocatalysts.
Abstract Highly efficient Ag-doped ZnO (Ag-ZnO)/sulfurized graphitic C3N4 heterostructure photoca... more Abstract Highly efficient Ag-doped ZnO (Ag-ZnO)/sulfurized graphitic C3N4 heterostructure photocatalyst was synthesized in a two-step hydrothermal route. Initially, Ag (1–9%) was doped into ZnO nanostructure and checked photocatalytic properties. 7% Ag-doped ZnO (7Ag-ZnO) NPs shown best photocatalytic methylene blue (MB) dye degradation under visible radiation, so, it was selected for forming composite with S-g-C3N4. In 1st step, S-g-C3N4 was synthesized by calcinating. In the 2nd step, 7Ag-ZnO/S-g-C3N4 heterostructure photocatalyst was formed by in situ formation of 7Ag-ZnO NPs in the presence of different contents of S-g-C3N4 (3.5–75 wt%) through hydrothermal route. As a result of 7Ag-ZnO/S-g-C3N4 heterostructure, a large number of catalytic active sites were generated for photocatalytic degradation. Interestingly, the 7% Ag-ZnO nanoparticles (NPs) with 25% S-g-C3N4 exhibited 97% MB degraded within 40 min, which was degraded up to 57% by 7Ag-ZnO alone. Moreover, the photo corrosion of ZnO NPs was inhibited by doping with Ag and coupling with S-g-C3N4.
Abstract Fast pyrolysis has appeared as a promising technology for bio-fuels and bio-based chemic... more Abstract Fast pyrolysis has appeared as a promising technology for bio-fuels and bio-based chemicals production. This paper reports tea waste (TW) as a promising source of phenolic-rich bio-oil production via catalytic fast pyrolysis in fluidized bed reactor. TG-FTIR analysis is applied to optimize pyrolysis temperature for phenolic-rich bio-oil production and maximum phenols yield (17.3 %) was obtained at 500 °C. Meanwhile, bio-oils are produced at each corresponding temperatures of TG-FTIR analysis and GC–MS analysis is performed to examine consistency and authenticity of TG-FTIR results. Moreover, catalytic effect of activated carbon + KOH (AC-K) with different biomass-to-catalyst ratio was examined to optimize most efficient ratio at 500 °C and maximum phenol contents (39.72 %) were obtained at 1:6 ratio of biomass-to-catalyst as compared to non-catalytic pyrolysis (23.85 %). Moreover, effect of temperature on product distribution was examined and maximum liquid yield (40.7 %) was obtained at 500 °C. Furthermore, switchable hydrophilic solvents (SHS) were used to isolate phenols from bio-oil with 95.02 % yield calculated by GC–MS analysis. The elemental analysis and high heating value (HHV) of the crude and residue bio-oil were determined. The carbon contents and HHV of residue bio-oil were increased to 67.3 % and 13.7 MJ/Kg from 46.2 % and 10.38 MJ/Kg respectively while; oxygen contents were decreased to 19.7 from 45.3 % demonstrating its potential for fuel application.
Abstract The development of cheap and effective catalysts is one of the major challenges to boost... more Abstract The development of cheap and effective catalysts is one of the major challenges to boost up electrocatalytic oxygen evolution reaction (OER). In this study, we synthesized phosphorus incorporated nickel sulfide (Ni3S2@Ni5P4/NF) composite via a simple one-step hydrothermal treatment for electrocatalytic oxygen evolution reaction in basic media. The newly synthesized Ni3S2@Ni5P4/NF composite catalyst shows a remarkable OER activity with an overpotential of 399 mV at a current density of 50 mA cm-2. Ni3S2@Ni5P4/NF also shows a Tafel slope of 75 mV dec-1 with long-term stability for more than 15 hours in alkaline media. The enhanced electrocatalytic activity of current system is among best catalysts based on Nickle sulfides and nickel phosphides according to our knowledge. Current enhancement can be attributed to fast electron transfer due to synergistic effect of Ni3S2 and Ni5P4 in the composite.
Critical role of the heterojunction interface of silver decorated ZnO nanocomposite with sulfuriz... more Critical role of the heterojunction interface of silver decorated ZnO nanocomposite with sulfurized graphitic carbon nitride heterostructure materials for photocatalytic a p p l i c a t i o ns ,
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
The catalytic decomposition of formic acid to generate syngas (a mixture of H2 and CO) is a highl... more The catalytic decomposition of formic acid to generate syngas (a mixture of H2 and CO) is a highly valuable strategy for energy conversion. Syngas can be used directly in internal combustion engines or can be converted to liquid fuels, meeting future energy challenges in a sustainable manner. Herein, we report the use of homogeneous molecular iron catalysts combined with a CdS nanorods (NRs) semiconductor to construct a highly efficient photocatalytic system for direct conversion of formic acid to syngas at room temperature and atmospheric pressure. Under optimal conditions, the photocatalytic system presents an activity of 150 mmol gcatalyst-1 h-1 towards H2 , and an apparent quantum yield (AQY) of 16.8 %, making it among the most active noble-metal-free photocatalytic systems for H2 evolution from formic acid under visible light. Meanwhile, these iron-based molecular catalysts also demonstrate remarkable enhancement in CO evolution with robust stability. The mechanistic role of the molecular catalyst is further investigated by using cyclic voltammetry, which suggests the formation of FeI species as the key step in the catalytic conversion of formic acid to syngas.
Two dimensional (2D) nanomaterials have interesting properties due to their lateral dimensions. P... more Two dimensional (2D) nanomaterials have interesting properties due to their lateral dimensions. Pure self-assembled L-cysteine stabilized covellite nanoplates (CuS@L-Cys NPs) and L-cysteine stabilized chalcocite nano leaves (Cu 2 S@L-Cys NLs) were synthesized by using a template free, the facile hydrothermal route with the best control of size, phase purity structure, morphology, and electrochemical properties. Novel CuS@L-Cys NPs and Cu 2 S@L-Cys NLs snowflakes dendrites were synthesized by varying synthetic parameters such as solvent, temperature (100-180°C), reaction time (8-24 h), pH of reaction medium (7-14), the concentration of base (0.1-2.4 mL NH 3) and concentration of thiourea (1-4 mmol). By changing these factors, different morphologies such as irregular, regular, trigonal, hexagonal leaf and snowflakes dendrites like shapes were observed.
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2020
Abstract Template-free, the facile hydrothermal route was used for the synthesis of pure self-ass... more Abstract Template-free, the facile hydrothermal route was used for the synthesis of pure self-assembled l -cysteine stabilized chalcocite nanoleaves (Cu2S@L-Cys NLs) with the best control of size, phase purity structure, morphology, and electrochemical properties. Effect of temperature (100–180 °C) and reaction time (8−24 h) were studied on the morphology of chalcocite Cu2S@L-Cys NLs snowflakes dendrites. By changing these factors, different morphologies such as irregular, regular, trigonal, hexagonal nanoleaf, and snowflakes dendrites like shapes were observed. Cu2S@L-Cys NLs were fabricated by using ethylenediamine (EDA) as a solvent. The photocatalytic performances of as-prepared Cu2S@L-Cys snowflake dendrites (NL3) and Cu2S@L-Cys irregular hexagram (NL4) in the degradation of methyl orange (MO) were examined under visible light. The noteworthy, unique bandgap (Cu2S@L-Cys snowflake dendrites NLs (1.55 eV) and Cu2S@L-Cys irregular hexagram NLs (1.58 eV) and the special morphology of Cu2S@L-Cys NLs increases the active sites for adsorption of dye, which causes extraordinary degradation activity. Furthermore, the l -cysteine (L-Cys) protective layer could efficiently alleviate the photocorrosion of Cu2S, giving rise to excellent stability. Cu2S@L-Cys NLs were reused successfully for photodegradation of dye due to the recycling ability of Cu2S@L-Cys NLs. The Cu2S@L-Cys snowflake dendrites NLs showed improved photocatalytic activity as compared to Cu2S@L-Cys irregular hexagram NLs. The improved surface area of Cu2S@L-Cys snowflake dendrites NLs, compared to that of the Cu2S@L-Cys irregular hexagram NLs, may be ascribed to the fact that snowflakes dendrites can support the growth and more surface-active sites of Cu2S@L-Cys. These results strongly suggest that the Cu2S@L-Cys snowflake dendrites are promising candidates for photocatalytic dye degradation.
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
A contrapositionally substituted derivative of cyclohexa-meta-phenylene ([6]CMP) was synthesized ... more A contrapositionally substituted derivative of cyclohexa-meta-phenylene ([6]CMP) was synthesized by an intramolecular Yamamoto coupling reaction of an appropriate terphenyl unit containing a trimethylsilyl substituent. Iododesilylation of the trimethylsilyl groups of the product with iodine monochloride was used to incorporate iodo groups, an important functionality for metal-catalyzed coupling reactions. The iodo groups were also converted into a (pinacolato)boryl groups, another important functionality for coupling reactions. The diborylated [6]CMP is expected to be a versatile potential comonomer and a precursor for the synthesis of CMP-based materials. The synthetic route to the disubstituted [6]CMP included lithiation, Pd-catalyzed borylation, Suzuki coupling, and Yamamoto coupling. The structure of the product was established by NMR spectroscopy and mass spectrometry.
The aims of this study is to investigate the effects of functional groups like eC]Ce and CeOH on ... more The aims of this study is to investigate the effects of functional groups like eC]Ce and CeOH on variation of higher heating values (HHV) of organic compounds. HHV of fuel hydrocarbons, gaseous and liquids including single bonded and multiple bonded carbons and green tea polyphenols (GTP) were determined by using Bomb Calorimeter. It was observed that, multiple bonded carbon and oxygen bonded carbon i.e. eC]Ce and eCeOe result in less carbon reduced state while, also increase endothermicity of reactants by changing hybridization state with more s-character and hence, contribute to lower level of HHV. Besides, hydrogen bonding was also considered as the major cause of the difference in HHV of fuel hydrocarbons having the same molecular formula but different oxygen-bearing functional groups due to structure stabilization. These statements were further supported by the combination of Fourier transform infra-red spectra (FTIR) and HHV calculation of raw GTP (set as a representative of biomass) and its solid products obtained at 250°C and 350°C by thermal treatment done by using high temperature tube furnace.
Photocatalytic hydrogen (H2) evolution is a promising approach for future sustainable energy util... more Photocatalytic hydrogen (H2) evolution is a promising approach for future sustainable energy utilization. However, it is still a great challenge to develop efficient and stable metal-free photocatalysts with broadband solar absorption in the visible region for H2 production. Metal-free graphene quantum dot (GQD) is an emerging candidate for this purpose because of its good water-solubility and tunable band gap. On the other hand, metal phosphides (Ni2P, Co2P, etc) have been demonstrated as novel noble-metal-free cocatalysts for water splitting, which can efficiently separate electron-hole pairs and enhance the photocatalytic activities. Herein, we report for the first time on the use of OH-functionalized GQDs (OH-GQDs) photosensitizer coupled with Ni2P nanoparticles for photocatalytic H2 production with λ > 420 nm light. The H2 production rate is ~94 times higher than that of bare OH-GQDs, which is even comparable to that of OH-GQDs with 1.0 wt% Pt cocatalyst. This enhancement is probably due to the semiconductor-cocatalyst interface interaction between Ni2P and OH-GQDs to facilitate efficient charge transfer process.
Noble-metal-free cobalt nitride (Co3N) can be used as a novel cocatalyst on CdS nanorods for phot... more Noble-metal-free cobalt nitride (Co3N) can be used as a novel cocatalyst on CdS nanorods for photocatalytic H2production in water under visible light irradiation.
Photocatalytic production of hydrogen by water splitting is a promising pathway for the conversio... more Photocatalytic production of hydrogen by water splitting is a promising pathway for the conversion of solar energy into chemical energy. However, the photocatalytic conversion efficiency is often limited by the sluggish transfer of the photogenerated charge carriers, charge recombination, and subsequent slow catalytic reactions. Herein, we report a highly active noble-metal-free photocatalytic system for hydrogen production in water. The system contains a water-soluble nickel complex as a molecular cocatalyst and zinc sulfide on 1D cadmium sulfide as the heterojunction photocatalyst. The complex can efficiently transport photogenerated electrons and holes over a heterojunction photocatalyst to hamper charge recombination, leading to highly improved catalytic efficiency and durability of a heterojunction photocatalyst- molecular cocatalyst system. The results show that under optimal conditions, the average apparent quantum yield was approximately 58.3 % after 7 h of irradiation with ...
Dalton transactions (Cambridge, England : 2003), Jan 9, 2016
Photocatalytic hydrogen production via water splitting has attracted much attention for future cl... more Photocatalytic hydrogen production via water splitting has attracted much attention for future clean energy application. Herein we report a noble-metal-free photocatalytic hydrogen production system containing a simple bidentate cobalt Schiff base complex as the molecular cocatalyst, CdS nanorods as the photosensitizer, and ascorbic acid as the electron donor. The system shows highly enhanced photocatalytic activity compared to pure CdS NRs under visible light (λ > 420 nm). Under optimal conditions, the turnover numbers (TONs) for hydrogen production reached ∼15 200 after 12 hours of irradiation, and an apparent quantum yield of ∼27% was achieved at 420 nm monochromatic light. Steady-state photoluminescence (PL) spectra indicated efficient charge transfer between the excited CdS NRs and the cobalt cocatalyst for improved hydrogen production. Spectroscopic studies of the photocatalytic reaction revealed the reduction of the Co(ii) complex to Co(i) species, which are probably activ...
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