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Bio-inspired carbon doped graphitic carbon nitride with booming photocatalytic hydrogen evolution
摘要： In this work, kapok fiber (KF), known as a versatile biomass, has been mixed with melamine to produce carbon modified graphitic carbon nitride (CCN) by one-step pyrolysis. The bio-char ribbon edges formed after the decomposition of KF act as the substrate for the epitaxial growth of CCN. The photocatalytic activity in hydrogen (H2) generation from water splitting has been investigated. Nash Equilibrium from Game Theory has been firstly applied in the analysis of the H2 generation rates among catalysts. The bio-char ribbon edges at the thin CN layers after carbon doping from KF decomposition improve the charge separation and transfer for the surface H2 generation reaction. The CCN exhibits superior visible-light-driven photocatalytic activity and the H2 evolution rate (18.89 μmol/h) is 67.5 times higher than that of the pristine CN (0.28 μmol/h). The apparent quantum yields are calculated to be 4.1%, 1.4%, 0.66% for monochromatic light λ= 420, λ= 470 and λ= 550 nm, respectively.
关键词： kapok fiber,carbon doping,carbon nitride,Photocatalysis
更新于2025-09-23 15:22:29
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Physical and electrical properties of nitrogen-doped hydrogenated amorphous carbon films
摘要： Nitrogen-doped hydrogenated amorphous carbon films (a-C:H:N) have been prepared by a plasma-activated chemical vapor deposition technique (PACVD) by using a plasma beam source (PBS). The properties of the a-C:H:N films were changed by varying the total pressure, the substrate temperature (100 °C, 300 °C) and nitrogen partial pressure p(N2) by adding nitrogen to the precursor acetylene (C2H2). For the investigations, a-C:H:N films have been deposited onto glass slides and doped silicon wafers. The deposition rate decreased with increasing nitrogen content in the N2/C2H2 gas mixture and with decreasing total pressure. The elemental composition of two sample series (300 °C) has been analyzed with Elastic Recoil Detection Analysis (ERDA). The highest N content and N/C ratio was estimated to be 16 at.% and 0.25 at the highest p(N2), respectively. Microhardness measurements showed that the hardness decreased with increasing p(N2). Electrical resistance of the a-C:H:N films was measured by 4-point probe. Electrically conductive coatings have been obtained by nitrogen-doped a-C:H films at higher substrate temperature (300 °C). The electrical resistance of the a-C:H:N films also decreases with decreasing total pressure, with the lowest value being about 1 Ohm cm. The film density was determined by means of X-ray reflectometry (XRR).
关键词： PACVD,carbon nitride films,electrical conductivity,DLC,carbon films,XRR
更新于2025-09-23 15:22:29
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Liquid exfoliation of g-C3N4 nanosheets to construct 2D-2D MoS2/g-C3N4 photocatalyst for enhanced photocatalytic H2 production activity
摘要： Although graphitic carbon nitride (g-C3N4) is an attractive photocatalyst for solar H2 generation, the preparation of g-C3N4 nanosheets via a “green” and simple method as well as the construction of highly-efficient g-C3N4-based photocatalysts are still challenges. In this study, g-C3N4 nanosheets prepared by a simple probe sonication assisted liquid exfoliation method were used to construct 2D-2D MoS2/g-C3N4 photocatalyst for photocatalytic H2 production. The 2D-2D MoS2/g-C3N4 photocatalyst containing 0.75% MoS2 showed the highest H2 evolution rate of 1155 μmol·h-1·g-1 with an apparent quantum yield of 6.8% at 420 nm monochromatic light, which is much higher than that of the optimized 0D-2D Pt/g-C3N4 photocatalyst. The high photocatalytic H2 production activity of 2D-2D MoS2/g-C3N4 photocatalyst can be attributed to the large surface area and the formed 2D interfaces between MoS2 and g-C3N4 nanosheets. As demonstrated by photoluminescence quenching and time-resolved fluorescence decay studies, the 2D interfaces can accelerate the photoinduced charge transfer, resulting in the high photocatalytic H2 production performance. This study provides a new strategy in developing highly-efficient g-C3N4-based photocatalysts for H2 production via using 2D nanojunction as a bridge to promote the photoinduced charge separation and transfer.
关键词： Hydrogen generation,Molybdenum disulfide,Graphitic carbon nitride,Photocatalysis,2D photocatalyst
更新于2025-09-23 15:22:29
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Strengthened spatial charge separation over Z-scheme heterojunction photocatalyst for efficient photocatalytic H2 evolution
摘要： Graphitic carbon nitride (g-C3N4) is a very promising earth abundant and visible light response photocatalyst for H2 production. Fabricating novel nanostructure or combining with other semiconductors have been attempted to further enhance its activity. α-FeOOH, due to its structures greatly facilitating electrolyte transport, has been widely used as an excellent OER cocatalyst assisting the PEC water splitting process. However, to the best of our knowledge, it has not been attempted in photocatalytic H2 generation. Herein, g-C3N4 modi?ed with β-FeOOH was designed for the ?rst time for photocatalytic H2 production. It showed H2 production rate as 2.02 mmol·h?1·g?1, which was almost 6 times of pure g-C3N4. The signi?cantly promoted catalytic activity was ascribed to the greatly enhanced charge separation e?ciency by forming spatial separated reservoirs of photo activated electrons and holes in the Z-scheme heterojunction, corresponding to the conduction band of g-C3N4 and the valence band of β-FeOOH, respectively. Our work should be valuable for fabricating visible-light response heterojunction based photocatalysts with better photocatalytic performance.
关键词： Hydrogen evolution,β-FeOOH,Graphitic carbon nitride,Photocatalysis,Heterojunction
更新于2025-09-23 15:22:29
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Layered Double Hydroxides Decorated Graphic Carbon Nitride Film as Efficient Photoanodes for Photoelectrochemical Water Splitting
摘要： In the present work, we investigate the graphic carbon nitride (g-CN) film as photoanode to catalyze the photoelectrochemical (PEC) water oxidation and study the influence of NiCo layered double hydroxides (NiCo-LDH) layer on the performance. The g-CN film with good quality and intimate contact with substrate was in-situ prepared via solvothermal process and subsequent calcination. NiCo-LDH is further decorated on the g-CN film through cathodic electrochemical deposition to work as co-catalyst. The g-CN/NiCo-LDH composite with optimized NiCo-LDH loading amount exhibits a photocurrent of 11.8 μA cm-2 at 0.6 V vs. SCE, which is 2.8 times of bare g-CN. Characterizations and performance tests demonstrate that NiCo-LDH promoted reaction kinetics and charge separation. The results provide an effective strategy to improve the photoelectrochemical water oxidation performance of g-CN through NiCo-LDH co-catalyst. This work to investigate the photoelectrochemical water oxidation is of great significance toward explore the overall water splitting on the g-CN film.
关键词： Layered double hydroxides,Solvothermal process,Photoelectrochemical water oxidation,Co-catalyst,Graphitic carbon nitride
更新于2025-09-23 15:22:29
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Photocatalytic hydrogen evolution assisted by aqueous (waste)biomass under simulated solar light: Oxidized g-C3N4 vs. P25 titanium dioxide
摘要： Oxidized graphitic carbon nitride (o-g-C3N4) and Evonik AEROXIDE? P25 TiO2 were compared for lab-scale photocatalytic H2 evolution from aqueous sacrificial biomass-derivatives, under simulated solar light. Experiments in aqueous starch using Pt or Cu–Ni as the co-catalysts indicated that H2 production is affected by co-catalyst type and loading, with the greatest hydrogen evolution rates (HER) up to 453 and 806 μmol g?1 h?1 using TiO2 coupled with 3 wt% Cu–Ni or 0.5 wt% Pt, respectively. Despite the lower surface area, o-g-C3N4 gave HERs up to 168 and 593 μmol g?1 h?1 coupled with 3 wt% Cu–Ni or 3 wt% Pt. From mono- and di-saccharide solutions, H2 evolution was in the range 504–1170 μmol g?1 h?1 for Pt/TiO2 and 339–912 μmol g?1 h?1 for Cu–Ni/TiO2, respectively; o-g-C3N4 was efficient as well, providing HERs of 90–610 μmol g?1 h?1. The semiconductors were tested in sugar-rich wastewaters obtaining HERs up to 286 μmol g?1 h?1. Although HERs were lower compared to Pt/TiO2, a cheap, eco-friendly and non-nanometric catalyst such as o-g-C3N4, coupled to non-noble metals, provided a more sustainable H2 evolution.
关键词： Biomass,Graphitic carbon nitride,Hydrogen,Photocatalysis,Solar light,Titanium dioxide
更新于2025-09-23 15:22:29
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Tailoring Grain Boundary Chemistry of Polymeric Carbon Nitride for Enhanced Solar H2 Production and CO2 Reduction
摘要： Photocatalytic water splitting is a promising and clean way to mimic the plant photosynthesis in a sustainable manner. Improvements of the quantum efficiency and optical absorption in the relevant range are certainly the further steps to approach practicality. Here, we reported that these issues can be readily addressed when 5-aminotetrazole, a monomer with still higher nitrogen content, is used for the synthesis of carbon nitride. The molten salt mixture NaCl/KCl is used as a high temperature solvent to tailor the grain boundary structure and chemistry. Visible light quantum efficiency for H2 production of 0.65 could be obtained in the presence of K2HPO4 as double layer modifier. This value is very high, considering that this number is a convolute of light to charge couple conversion, charge localization, as well as a successful oxidation and reduction reaction.
关键词： H2 production,Grain boundary,Polymeric carbon nitride,Photocatalysis,Salt melt
更新于2025-09-23 15:22:29
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Tailoring Grain Boundary Chemistry of Polymeric Carbon Nitride for Enhanced Solar H2 Production and CO2 Reduction
摘要： Photocatalytic water splitting is a promising and clean way to mimic the plant photosynthesis in a sustainable manner. Improvements of the quantum efficiency and optical absorption in the relevant range are certainly the further steps to approach practicality. Here, we reported that these issues can be readily addressed when 5-aminotetrazole, a monomer with still higher nitrogen content, is used for the synthesis of carbon nitride. The molten salt mixture NaCl/KCl is used as a high temperature solvent to tailor the grain boundary structure and chemistry. Visible light quantum efficiency for H2 production of 0.65 could be obtained in the presence of K2HPO4 as double layer modifier. This value is very high, considering that this number is a convolute of light to charge couple conversion, charge localization, as well as a successful oxidation and reduction reaction.
关键词： Grain boundary,Salt melt,Photocatalysis,H2 production,Polymeric carbon nitride
更新于2025-09-23 15:22:29
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Visible Light Driven Reductive (Cyclo)Dimerization of Chalcones Over Heterogeneous Carbon Nitride Photocatalyst
摘要： Single electron reduction of chalcones to the respective radical anions is a useful technique to activate these molecules toward subsequent transformations. Herein, a metal free photocatalytic version of chalcones reduction in the presence of triethanolamine as a convenient electron donor and using heterogeneous carbon nitride visible light photocatalyst is presented. The reaction proceeds via a long lived radical species of the heterogeneous organic semiconductor. The scope of the reaction was studied and regioselectivity of the chalcone radicals coupling was investigated. (1) Ten chalcones gave selectively poly substituted cyclopentanoles with 31-73% isolated yield; (2) Two chalcones bearing electron-donor groups, 4-MeOC6H4 and 2-thienyl, gave selectively the β-ketodienes in 42% and 53% isolated yield, respectively; (3) Pentafluorophenyl substituted chalcone gave exclusively the product of the radicals coupling followed by hydrogen transfer from triethanolamine – hexane-1,6-dione in 65% isolated yield. Reductive cross cyclodimerization of a mixture of two different chalcones proceeded regioselectively with the formation of one product out of four possible. The mechanism was investigated by cyclic voltammetry and linear sweep voltammetry and suggests that the reaction proceed through proton coupled electron transfer.
关键词： cyclopetanole,organic photoredox catalysis,chalcone,carbon nitride,proton coupled electron transfer
更新于2025-09-23 15:22:29
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Facile Preparation of Unsubstituted Iron(II) Phthalocyanine/Carbon Nitride Nanocomposites: A Multipurpose Catalyst with Reciprocally Enhanced Photo/Electrocatalytic Activity
摘要： The development of new catalytic materials is conducive to solving the global energy crisis and environmental problems. In this work, multipurpose catalyst unsubstituted iron(II) phthalocyanine/carbon nitride nanosheet (FePc/CN) nanocomposites were prepared by utilizing concentrated sulfuric acid as an ideal solvent of CN and unsubstituted FePc. Such FePc/CN nanocomposites exhibited improved photo/electrocatalytic activity which was enhanced reciprocally: the photocatalytic activity of CN was promoted by FePc anchoring, and the electrocatalytic activity of FePc was improved by CN doping. The photocatalytic performance of FePc/CN?0.3 nanocomposites was about 6.4 and 1.7 times as high as FePc and CN, which was attributed to two reasons: (1) the anchoring FePc on CN extended the visible-light absorption region of CN, (2) the electron transfer from excited FePc to CN hindered charge carriers recombination and thus enhanced the photoinduced carrier separation efficiency. Relative to FePc and CN, the onset potential of FePc/CN?0.3 was positively shifted by 52 and 174 mV, such higher oxygen reduction reaction activity was due to the uniform dispersion of FePc on the supporting material CN without aggregation, which led to improved conductivity and stability of nanocomposites. This approach will contribute to an inexpensive and convenient synthetic strategy of transition-metal-based nanostructures for functional applications in photovoltaic, electrochemical, and catalytic fields.
关键词： Unsubstituted iron(II) phthalocyanine,Oxygen reduction reaction,Multipurpose catalyst,Photocatalytic performance,Carbon nitride nanosheet
更新于2025-09-23 15:22:29