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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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Visible-light-driven selective oxidation of methane to methanol on amorphous FeOOH coupled m-WO3
摘要： Direct conversion of methane into value-added fuels or chemicals under ambient conditions remains a great challenge. Constructing solar-energy-driven catalytic systems is considered as a promising strategy, but the conversion e?ciency and products selectivity are still low, especially for producing alcohol derivatives. Herein, to promote the photocatalytic activity of methane partial oxidation to methanol, a series of FeOOH/m-WO3 consisting of ordered mesoporous WO3 (m-WO3) and highly dispersed amorphous FeOOH were synthesized by using KIT-6 silica as hard template. The prepared FeOOH/m-WO3 catalysts exhibit dramatically improved visible-light catalytic activities toward selective oxidation methane into methanol in the presence of H2O2. A methane conversion rate of 238.6 μmol·g?1·h?1 is achieved over the optimal 1.98% FeOOH/m-WO3, which is 3 times higher than that of pristine m-WO3 (79.2 μmol·g?1·h?1). Moreover, a methanol production rate of 211.2 μmol·g?1·h?1 with a selectivity of 91.0% is obtained on the optimum catalyst under 4 h visible-light irradiation. Signi?cantly, the greatly improved methane conversion and methanol production can be attributed to e?cient electron migration from the conduction band of m-WO3 to highly dispersed FeOOH, evidenced by in-situ XPS analysis, transient photocurrent response and photoluminescence spectra. Furthermore, based on radicals trapping experiments and electron spin resonance (ESR) results, methane is primarily activated by photoholes accumulated on the valence band of m-WO3 to generate methyl radicals (·CH3) and the produced hydroxyl radicals (·OH) via decomposing H2O2 by photoelectrons on FeOOH surface are predominant oxidant for methanol generation. Desired methanol is selectively produced via radicals reaction between ·CH3 and ·OH.
关键词： WO3,Methane,Methanol,Visible-light-driven,Amorphous FeOOH
更新于2025-09-19 17:13:59
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Hydrogen Production System by Light‐Induced α‐FeOOH Coupled with Photoreduction
摘要： Solar driven catalysts on semiconductors to produce hydrogen are considered as a means to solve environmental issues. In this study, H2 production coupling with oxygen consumption by noble metal-free α-FeOOH was demonstrated even though the conduction band edge was lower than the reduction potential of H+ to H2. For activation of α-FeOOH, an electron donor, Hg-Xe irradiation, and low pH (~5) were indispensable factors. The H2 production from H2O was confirmed by GC-MS using isotope-labeled water (D2O) and deuterated methanol. The α-FeOOH synthesized by coprecipitation method showed 25 times more active than TiO2. The photocatalytic activity was stable for over 400 h. Our study suggests that α-FeOOH known as rust can produce H2 by light induction.
关键词： α-FeOOH,Photocatalyst,photoreduction
更新于2025-09-12 10:27:22
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Transformation pathway and degradation mechanism of methylene blue through β-FeOOH@GO catalyzed photo-Fenton-like system
摘要： To enhance the catalytic and separation properties of akaganéite nanoparticles, rice spike-like akaganéite impregnated graphene oxide (β-FeOOH@GO) nanocomposite was fabricated through facile hydrolysis. The apparent first-order decolorization rate of methylene blue (MB) in β-FeOOH@GO catalyzed photo Fenton-like system was 0.6322 min-1 about 3 folds that of prinstine β-FeOOH nanoparticles. The degradation intermediates of MB adsorbed on the solid surface of β-FeOOH@GO were comprehensively identified with time of flight-secondary ion mass spectroscopy (TOF-SIMS) for the first time. Newly identified sulfoxide intermediates, sulphone intermediates and desulfurization intermediates and N-demethylaton or dedimethamine intermediates were reported for the first time. The proposed degradation pathway of MB predominantly proceeded with the rupture of phenothiazine rings oxided with ?OH, HO?? and singlet oxygen (1O2) radicals, which fully extending the reaction pathways proposed in previous work in literature. The enhanced catalytic activity of β-FeOOH@GO was ascribed to the formation of heterojunctions confirmed by the presence of Fe-O-C chemical bonds through X-ray photoelectron spectroscopy (XPS). The complete elimination of MB and its acute toxicity to Luminous bacteria showed that β-FeOOH@GO would be served as a highly efficient Fenton-like catalyst for treatment of high concentration refractory organic contaminant.
关键词： Degradation mechanism,Graphene oxide,Methylene blue,β-FeOOH,Photo-Fenton-like reaction
更新于2025-09-10 09:29:36