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Theoretical Modeling and Simulation of Atomically Dispersed Metallic Materials
Published in Wei Yan, Xifei Li, Shuhui Sun, Xueliang Sun, Jiujun Zhang, Atomically Dispersed Metallic Materials for Electrochemical Energy Technologies, 2023
Wen-Jin Yin, Gilberto Teobaldi, Li-Min Liu
In this section, a variety of applications of SACs involving photocatalysis and electrocatalysis of different reactions are discussed, including CO2 reduction, CO oxidation reaction, hydrogenation reaction, and other related reactions. Photocatalytic processes require a semiconductor to absorb a photon with energy higher than the band gap, exciting one electron from the valence into the conduction band, leaving one excited hole in the valence band. These excited electrons and holes then transmit to the surface of the semiconductor encountering adsorbed reactant molecules, thus triggering the reduction and oxidation processes. Different from the photocatalytic case, electrocatalysis implies the presence of an electrochemical reaction on or at the catalyst.52 This in turn requires that the catalyst can take an electrical current, along with protons/electrons, to achieve the reaction intermediates/products. Good electrocatalysts generally have the following qualities: fast charge transfer capability, high active site density, and high electrical conductivity. SACs have been reported to show excellent performances for several electrochemical reactions, including the ORR, the OER, the HER, the NRR, and the CRR. Table 3.1 summarizes the binding energy and rate-determining steps of some typical electrochemical reactions on different SACs.
Laser-Induced Graphene for Electrocatalysis Applications
Published in Ruquan Ye, James M. Tour, Laser-Induced Graphene, 2020
Electrocatalysts play a key role in improving the energy conversion efficiency and production rate of chemical reactions. The development of highly active electrocatalysts has important implications in areas such as energy storage and chemical synthesis. For example, the hydrogen evolution reaction (HER) and CO2 reduction are sought to store intermittent electricity as a fuel or to form chemical commodities. Oxygen reduction reaction (ORR), as discussed in Chapter 3, was used in metal-air batteries. All these reactions require the development of electrocatalysts to reduce the overpotentials and improve the reaction kinetics. In this chapter, we will introduce the applications of laser-induced graphene (LIG) in various chemical reactions. The first is based on LIG, and the second is based on LIG composites.
Carbon Nanotube-Metal Oxide Hybrid Nanocomposites Synthesis and Applications
Published in Zainovia Lockman, 1-Dimensional Metal Oxide Nanostructures, 2018
Zaid Aws Ali Ghaleb, Mariatti Jaafar
Electrocatalyst is a catalyst depending on electrochemical reaction. It is a specific form of catayst that accelerates the reactions on the interface between electrode and electrolyte. As an electrocatalyst, two properties are required: (1) electrical conductivity and electron transfer freely; (2) efficient catalytic activity towards target substrate. Metal oxide such as TiO2 and SnO2 are widely used as electrocatalysts due to some advantages such as low cost and facile preparation. Carbon nanotubes endow CNT/metal oxide composite enhancements on electrocatalysis due to electric conductivity and fast electron transfer (Hu and Guo, 2011). For example, Yang et al. (2017) examined the electrocatalytic activity of MWCNTs filters for remediation of aqueous phenol in a sodium sulfate electrolyte. MWCNTs were loaded with antimony-doped tin oxide and bismuth- and antimony-codoped tin oxide via electrosorption. This study showed that CNT filters can be used as anodes for electrocatalytic water treatment, and their performance is significantly improved simply by loading them with metal-doped SnO2 particles. Another example, Mo et al. (2009) prepared ZnO/MWCNTs nanocomposite via a hydrothermal process and found remarkable electrocatalytic activity towards H2O2 by comparing it with bare MWCNTs. Subsequently, Ma and Tian (2010) discovered that ZnO-MWCNTs/Nafion film showed fast and excellent electrocatalytic activity towards H2O2 and trichloroacetic acid.
Catalytic applications of phosphorene: Computational design and experimental performance assessment
Published in Critical Reviews in Environmental Science and Technology, 2023
Monika Nehra, Neeraj Dilbaghi, Rajesh Kumar, Sunita Srivastava, K. Tankeshwar, Ki-Hyun Kim, Sandeep Kumar
Electrocatalysts play a significant role in different energy conversion technologies, mainly in the production of chemicals and fuels. In comparison to conventional electrocatalyst (e.g. platinum and iridium), the recent research efforts are directed for development of cost-effective and highly efficient phosphorene-based electrocatalysts. Among different TMDs, mono-/few layer MoS2 exhibits excellent electrocatalytic activity toward HER only in acidic solutions. However, the performance of most of TMDs (like MoS2) is still poor in alkaline media or as an OER catalysts (Prasannachandran et al., 2020). Phosphorene is the first in pnictogen family (involving arsenene, bismuthine, antimonene, and phosphorene) to be explored for its electrochemistry where a lone inherent periodic signal was found (Wang et al., 2015). This inherent electrochemistry was not found in case of pristine graphene or found negligible in case of graphitic carbon nitride over a stable and large window (Chia & Pumera, 2018). Here, recent investigations on the electrocatalytic activity of phosphorene are explored, mainly for oxygen evolution and hydrogen evolution reactions (Table 2).
Promotional role of gold in electrochemical methanol oxidation
Published in Catalysis, Structure & Reactivity, 2019
Samarjeet Siwal, Nishu Devi, Venkata K. Perla, Sarit K. Ghosh, Kaushik Mallick
These days, several efforts have been made by the scientists in the search of metal-free catalysts with comparable catalytic activity, like metal-based catalysts, for the next-generation electrocatalysis research and development. Metal-free CN shows remarkable catalytic activity for a variety of reactions such as photocatalytic hydrogen production [37,38] and fuel cell-based research [39,40]. In this current study, we demonstrate a stabilizer-free synthetic route of gold nanoparticles supported on CN. Both CN and gold–CN (Au-CN) were employed as anode catalysts for the oxidation of methanol where CN showed the catalytic performance for the title reaction and the gold particles acted as promoters for the reaction.