image: CdS spheres and CdS nanorods with different lengths were constructed by hydrothermal method and solvothermal process with varied reaction time, respectively. The medium-length CdS nanorods subjected to ultrasonic stimulation exhibits excellent piezocatalytic H2 evolution performance due to the strong piezoelectric potential and benign mechanical strain collecting ability. view more
Credit: Chinese Journal of Catalysis
Damaged ecosystems are sending signals of global climate crisis and energy scarcity to wake human beings up to respond by reducing excessive carbon dioxide and producing green sustainable energy. The enormous potential is maintained by piezocatalysis, the absence of daylight constraints and abundant energy sources, including vibration, water flow, friction, tidal power, water droplets and human movement. Piezocatalytic hydrogen evolution has emerged as a promising direction for the collection and utilization of mechanical energy and the efficient generation of sustainable energy throughout the day.
Piezoelectric materials for catalysis are emerging and enriching, including perovskite-type materials (e.g. BaTiO3, ZnSnO3, CH3NH3PbI3), wurtzite-type materials (e.g. ZnO, ZnS and CdS), two-dimensional (2D) materials (e.g. MoS2, Bi2WO6 and 2D black phosphorus) and organic polymer (e.g. poly(vinylidene fluoride) (PVDF), polydimethylsiloxane (PDMS) and graphite carbon nitride). Some wurtzite crystal materials with non-centrosymmetric (NCS) structure have been found to be promising piezocatalytic materials to alleviate the bottleneck of photocatalytic efficiency.
The typical NCS wurtzite structured CdS with a space group of P63mc and point group of 6mm shows piezoelectric effect, which is expected to effectively speed up the separation of carriers and increase the overall catalytic efficiency through piezoelectric polarization field. Unfortunately, the high-efficiency piezocatalytic hydrogen production of CdS-based materials has remained challenging so far, which is limited to the rapid recombination and deactivation of photogenerated carriers.
Recently, a research team led by Prof. Hongwei Huang from China University of Geosciences (Beijing) reported that two types of CdS nanostructures, namely CdS nanorods and CdS nanospheres, were prepared to probe the above-mentioned issues. Under ultrasonic vibration, CdS nanorods afforded a superior piezocatalytic H2 evolution rate of 175 μmol g-1 h-1 in the absence of any co-catalyst, which is nearly 2.8 times that of CdS nanospheres. The higher piezocatalytic activity of CdS nanorods is derived from their larger piezoelectric coefficient and stronger mechanical energy harvesting capability, affording a greater piezoelectric potential and more efficient separation and transfer of intrinsic charge carriers, as elucidated through piezoelectric response force microscope, finite element method, and piezoelectrochemical tests. This study provides a new concept for the design of efficient piezocatalytic materials for converting mechanical energy into sustainable energy via microstructure regulation. The results were published in Chinese Journal of Catalysis (https://doi.org/10.1016/S1872-2067(21)63976-1).
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About the Journal
Chinese Journal of Catalysis is co-sponsored by Dalian Institute of Chemical Physics, Chinese Academy of Sciences and Chinese Chemical Society, and it is currently published by Elsevier group. This monthly journal publishes in English timely contributions of original and rigorously reviewed manuscripts covering all areas of catalysis. The journal publishes Reviews, Accounts, Communications, Articles, Highlights, Perspectives, and Viewpoints of highly scientific values that help understanding and defining of new concepts in both fundamental issues and practical applications of catalysis. Chinese Journal of Catalysis ranks among the top six journals in Applied Chemistry with a current SCI impact factor of 8.271. The Editors-in-Chief are Profs. Can Li and Tao Zhang.
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