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Electrocatalysis and Photocatalysis
Published in Ramendra Sundar Dey, Taniya Purkait, Navpreet Kamboj, Manisha Das, Carbonaceous Materials and Future Energy, 2019
Ramendra Sundar Dey, Taniya Purkait, Navpreet Kamboj, Manisha Das
Similar to the steps of the HER process in acidic media, here also the reaction undergoes Volmer, Heyrovsky and Tafel reactions. Since the concentrations of protons are less in alkaline media, instead of H+, molecular H2O combines with an electron to result in an adsorbed hydrogen atom on the surface of the catalyst. This reaction is called the Volmer reaction: H2O(l)+e−+X→XHads+OH−(aq)+4e−(Volmerreaction)From the Volmer reaction for the generation of H2, the reaction undergoes two steps: Heyrovsky and Tafel reactions.
Single-Atom Catalysts on Nanostructure from Science to Applications
Published in Sam Zhang, Jyh-Ming Ting, Wan-Yu Wu, Functional Thin Films Technology, 2021
Yi-Sheng Lai, Anggrahini Arum Nurpratiwi, Yen-Hsun Su
The benchmark catalyst for HER is Pt-based catalysts which are very costly and also rare. Developing active, stable, and low-cost electrocatalysts for water splitting became an important issue. Hence, Sun et al. (2013) suggested using a method to produce isolated single Pt atoms on N-doped graphene using atomic layer deposition (ALD). They reported that the single Pt atom catalysts can enhance the HER catalytic activities and stability of up to 37 times compared to the commercial Pt/C catalysts. Another research for single Pt atoms on N-doped graphene support using ALD techniques was also conducted by Chang et al. (2014). Their research reported that HER performance was increased up to 13 times compared to the Pt/C catalysts.
Fundamentals of Water Electrolysis
Published in Lei Zhang, Hongbin Zhao, David P. Wilkinson, Xueliang Sun, Jiujun Zhang, Electrochemical Water Electrolysis, 2020
Xiaoxia Yan, Rida Javed, Yanmei Gong, Daixin Ye, Hongbin Zhao
The HER is the reaction that happens at the cathode during the electrocatalytic decomposition of water. In the twentieth century, people began to explore the mechanism of a hydrogen evolution reaction. Among them, Tafel discovered in 1905, and put forward, the cathodic hydrogen evolution reaction, in a research note he proposed overpotential and current density has a semi-log relationship: ΔФ = a + blgi. In addition, after discussion and deliberation by scholars, it is agreed that the main process of a hydrogen evolution reaction on the metal surface is as follows121,122:
Vibrational spectroscopy of free di-manganese oxide cluster complexes with di-hydrogen
Published in Molecular Physics, 2023
Sandra M. Lang, Thorsten M. Bernhardt, Joost M. Bakker, Bokwon Yoon, Uzi Landman
The direct conversion of solar energy into storable and renewable fuels is one of the main challenges of modern catalysis research. Inspired by natural photosynthesis, sun-light driven water oxidation followed by the hydrogen evolution reaction (HER, i.e. proton reduction) has attracted much interest and huge research efforts have been invested in this direction during the past decade (see e.g. Ref. [1–7] for recent review articles). Among the various processes involved in artificial photosynthesis the catalysis of the energy demanding water oxidation (reaction 1) represents one of the main challenges (see e.g. Ref. [1,6–10]). In nature, this half-reaction (i.e. the oxidative part of the water plus carbon dioxide redox reaction) is catalysed by the oxygen evolving complex (OEC), which is embedded in the protein structure of photosystem II (PS II). X-ray diffraction studies revealed that the OEC consists of an inorganic CaMn4O5 cluster surrounded by a network of amino acid residues and water molecules [11,12].
Scientometric review of transition metal oxides for hydrogen energy production
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2022
Hydrogen generation through water splitting has become a need of twenty-first century to meet the clean energy demand, especially solar-derived hydrogen evolution process. Transition metal oxides have been proven to be one kind of suitable catalysts for HER. Figure 1a presents the number of documents published in each year about transition metal oxide for HER from 1992 to March 2021. As indicated in this figure, the publication in the research of transition metal oxide catalysts (Fe, Co, Ti, Ni, Zr, Cu, Cr et al-based oxides) for HER was initiated in 1992 with a publication by Vijh. AK, Belanger. G, and Jacques. R (Vijh, Bélanger, and Jacques 1992). The voltametric behavior of HER was first investigatedon metallic conducting oxides from TinO2n-1 series with n = 4–6 byPrzyluski. J and Kolbrecka. K (Przyłuski and Kolbrecka 1993). The influence of titanium oxide’s reduction degree of electrolytic activity (n in TinO2n-1) for HER on these oxides was tested. The number of publications in this area did not experience any rapid increase until the 2010s. From then, more attention was paid to semiconductor photocatalysts and the activation of these catalytic materials. That is to say, the following catalysts including ZnO (Sanchez et al. 2010), TiO2 (Do et al. 2020) and titanium occupied perovskite oxides (Patial et al. 2020) were widely investigated for photocatalytic HER. Meantime, the mechanism investigations were rarely shown up and the stoichiometry changes of catalysts were the focus of attention. From Figure 1b, it is clear to see that the speed of research about this field was increased from 2015. During this period, more attention was paid to the development of nanostructured materials possess larger surface areas, thereby providing more active sites and promoting charge transfer process (Mistry et al. 2016).