Hydrogen is considered as a promising energy source with its high energy yield, renewable, environment friendly properties. TiO2 modified with noble metal and nonmetal is widely used. In this study, Pt and graphene (GN) were used to modify TiO2 nanoparticles. GN/TiO2 (TG), Pt-TiO2 (PT), Pt-GN/TiO2 (PTG) was successfully synthesized by modified Hummers' method, alcohol thermal and photodeposition method, respectively. The characterizations of the synthesized catalysts by UV-vis/DRS, components analysis, XRD and TEM analysis were conducted. Results showed the maximum hydrogen production rate was approximately 4.71 mmol h-1 g-1 when the Pt content was 1.0 wt.%. Higher and lower than 1.0 wt.% of Pt loading content both result in low efficiency of hydrogen production. The situation of graphene is similar to Pt. The optimal ratio for grapheme is 10 wt.%. The highest hydrogen production rate is 6.58 mmol h-1 g-1 by 1.5 wt.% Pt-5 wt.% GN/TiO2 (1.5PTG5), which is about 1.4 and 2.2 times higher than that of Pt-TiO2 and GN/TiO2 binary composites, respectively. The utilization of low-cost graphene can reduce the use of noble metal Pt in photocatalytic hydrogen production. The mechanism of Pt-GN/TiO2 for the improved photocatalytic activity is proposed. 0.1 g L-1 is found to be the optimum catalyst concentration for optimal hydrogen production.
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http://dx.doi.org/10.1166/jnn.2018.14556 | DOI Listing |
J Am Chem Soc
January 2025
State Key Laboratory of Catalysis, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, PR China.
A prevalent challenge in particulate photocatalytic water splitting lies in the fact that while numerous photocatalysts exhibit outstanding hydrogen evolution reaction (HER) activity in organic sacrificial reagents, their performance diminishes markedly in a Z-scheme water splitting system using electronic mediators. This underlying reason remains undefined, posing a long-standing issue in photocatalytic water splitting. Herein, we unveiled that the primary reason for the decreased HER activity in electronic mediators is due to the strong adsorption of shuttle ions on cocatalyst surfaces, which inhibits the initial proton reduction and results in a severe backward reaction of the oxidized shuttle ions.
View Article and Find Full Text PDFJ Phys Chem Lett
January 2025
School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China.
Electrochemical nitrogen conversion for ammonia (NH) synthesis, driven by renewable electricity, offers a sustainable alternative to the traditional Haber-Bosch process. However, this conversion process remains limited by a low Faradaic efficiency (FE) and NH yield. Although transition metals have been widely studied as catalysts for NH synthesis through effective electron donation/back-donation mechanisms, there are challenges in electrochemical environments, including competitive hydrogen evolution reaction (HER) and catalyst stability issues.
View Article and Find Full Text PDFACS Nano
January 2025
School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen 518000, China.
Electrochemical nitrate reduction (NORR) to ammonia presents a promising alternative strategy to the traditional Haber-Bosch process. However, the competitive hydrogen evolution reaction (HER) reduces the Faradaic efficiency toward ammonia, while the oxygen evolution reaction (OER) increases the energy consumption. This study designs IrCu alloy nanoparticles as a bifunctional catalyst to achieve efficient NORR and OER while suppressing the unwanted HER.
View Article and Find Full Text PDFBiopolymers
March 2025
Centro de Investigación en Química Aplicada, Saltillo, Coahuila, Mexico.
Exploring new ecological and simultaneous processes to modify wood fibers (WF) by-products is a required pathway toward circular economy and sustainability. Thus, plasma-activated water (PAW) and ultrasound (U) were employed as alternative methods to modify WF in a continuous process. Such treatments promoted the etching and cavities on the WF surface that destabilized the hydrogen bonds of the hemicellulose and lignin molecules, increasing the cellulose fraction.
View Article and Find Full Text PDFNat Commun
January 2025
WA School of Mines: Minerals, Energy and Chemical Engineering (WASM-MECE), Curtin University, Perth, WA, 6102, Australia.
Reducing green hydrogen production cost is critical for its widespread application. Proton-exchange-membrane water electrolyzers are among the most promising technologies, and significant research has been focused on developing more active, durable, and cost-effective catalysts to replace expensive iridium in the anode. Ruthenium oxide is a leading alternative while its stability is inadequate.
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