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Enhancement of visible‐light photocatalytic hydrogen production by CeCO3OH in g‐C3N4/CeO2 system
摘要： Promoting the separation of photo-generated carriers is significantly important to improve the efficiency of photocatalytic hydrogen production. Therefore, we prepared g-C3N4/CeCO3OH/CeO2 (CeCeCN) ternary nanocomposite via an easy synthetic way using g-C3N4 and CeO2 as reactants. A CeCO3OH layer was formed and resulted in the novel ternary photocatalyst. The CeCeCN composite shows superior photocatalytic (PC) H2 generation performance in sunlight excitation. The H2 evolution rate is about 764 μmol h-1 g-1, which is over 11 times larger than those of g-C3N4 and CeO2. Compared with g-C3N4 and CeO2, CeCeCN further shows a larger photo-response current density and a lower charge-transfer resistance. The remarkably increased photocatalytic property of CeCeCN is because of the efficient charge migration induced by the formed heterojunction. Our findings demonstrate that building multi-heterostructures can liberate more excited electrons for efficient hydrogen production under sunlight.
关键词： heterojunction,CeCO3OH,g-C3N4/CeCO3OH/CeO2,photocatalytic hydrogen evolution,ternary
更新于2025-09-04 15:30:14
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A Metal‐Organic‐Framework‐Derived g‐C3N4/α‐Fe2O3 Hybrid for Enhanced Visible‐Light‐Driven Photocatalytic
摘要： As one of the most efficient systems for photocatalytic hydrogen evolution, the Z-scheme system consisting of different semiconductors with a reversible donor-acceptor pair has attracted great attention. Considering for the nontoxicity and low cost of photocatalysts, a series of g-C3N4/α-Fe2O3 hybrids were rationally constructed based on the Z-scheme mechanism for the first time using a metal-organic framework template approach that can fine-tune the compositions and properties of the hybrids. An optimized hybrid, g-C3N4/α-Fe2O3-2, exhibited prominent photocatalytic water splitting performance with a visible light response. Under irradiation of visible light (λ > 420 nm), the hybrid shows a high durability and superior hydrogen production rate of 2066.2 μmol g-1 h-1 from water splitting, which is approximately three times greater than that of bulk g-C3N4 because of the effective separation of photo-excited charge carriers by two narrow bandgap semiconductors tightly coupled with the Z-scheme structural feature.
关键词： Z-scheme system,hydrogen evolution,g-C3N4/α-Fe2O3 hybrid,metal-organic frameworks
更新于2025-09-04 15:30:14
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One-step synthesis of petals-like graphitic carbon nitride nanosheets with triazole defects for highly improved photocatalytic hydrogen production
摘要： Reaction atmospheres during graphitic carbon nitride preparation can have a significant influence on the chemical composition and structure of the material, subsequently improving the photocatalytic activity. However, it is still a challenge to introduce an atmosphere by one-step heat-treated method to synthesis graphitic carbon nitride without additive gases. Herein, we developed a new one-step method to gather a variety of gases for preparing petals-like graphitic carbon nitride nanosheets (CNeC), such as CO(g), NH3(g) and H2O(g). NH3(g) and H2O(g) are respectively derived from melamine-cyanuric acid supermolecule during pyrolysis. The petals-like CNeC with more triazole defects (Nc) significantly increases the separation efficiency and the mobility of photogenerated photo-induced electron-hole pairs. Compared with the g-C3N4 calcined under nitrogen atmosphere (CNeN), CNeC has smaller grain, higher porosity with larger surface area, and remarkably longer lifetime of charge carriers. As expected, the product CNeC exhibited a hydrogen evolution rate of 1334 mmol g?1 h?1 under visible-light irradiation, which was 2.8 times higher activity than CNeN, as well as higher than most of the reported bulk g-C3N4.
关键词： Photocatalysis,g-C3N4,Triazole defects,Multiple gases,Hydrogen evolution
更新于2025-09-04 15:30:14
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Donor-π-acceptor dye-sensitized photoelectrochemical and photocatalytic hydrogen evolution by using Cu2WS4 co-catalyst
摘要： Photoelectrochemical and photocatalytic hydrogen evolution reaction (HER) have been investigated by using metal free donor-acceptor (D-A) and donor-p-acceptor (D-p-A) dyes, which are abbreviated as MC-32 and MC-048, respectively, sensitized TiO2 as a photocatalyst with or without Cu2WS4 co-catalyst. This co-catalyst is synthesized by a low-cost and simple hot injection method, under visible light illumination. The photoactivities of these dyes have been clarified according to their structural, optical and electrochemical properties. Photocatalytic activities have been slightly increased when added the Cu2WS4 co-catalyst (dye/TiO2/Cu2WS4). This catalytic activity is also compared to that of noble metal Pt (dye/TiO2/Pt). It has been found that 121 mmolg-1h-1, 179 mmolg-1h-1, 348 mmolg-1h-1, 212 mmolg-1h-1, 422 mmolg-1h-1 and 1139 mmolg-1h-1 hydrogen have been evolved by using MC-32/TiO2, MC-32/TiO2/Cu2WS4, MC-32/TiO2/Pt, MC-048/TiO2, MC-048/TiO2/Cu2WS4 and MC-048/TiO2/Pt, respectively.
关键词： Dye sensitization,Donor-p-acceptor dyes,Hydrogen evolution
更新于2025-09-04 15:30:14
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Green synthesis of g-C <sub/>3</sub> N <sub/>4</sub> -Pt catalyst and application to photocatalytic hydrogen evolution from water splitting
摘要： The g-C3N4-Pt photocatalyst was successfully prepared by the combination of a biosynthesis method and sol deposition, which were used for hydrogen evolution from water splitting. The layers of g-C3N4 are thinned and the Pt nanoparticles simultaneously become tightly bound to g-C3N4 by secondary calcination in the process of synthesizing the g-C3N4-Pt photocatalyst. Analysis of the morphological structure and instrumental characterization of the optical performance revealed that the Pt nanoparticles were successfully loaded and well dispersed on the surface of g-C3N4. Furthermore, the absorption wavelength range of the g-C3N4-Pt photocatalyst in visible light was widened and the absorption increased. The activity and photostability of the g-C3N4-Pt photocatalyst for hydrogen evolution under visible light irradiation (λ≥420 nm) were excellent. The rate of H2 evolution reached 582.4 mmol h?1 g?1, and the quantum efficiency (QE) reached 2.70% at 420 nm.
关键词： green synthesis,hydrogen evolution,visible-light photocatalysis,G-C3N4-Pt photocatalyst
更新于2025-09-04 15:30:14