Activity engineering to transition metal phosphides as bifunctional electrocatalysts for efficient water-splitting

At present, water splitting has been regarded as one of the most promising ways for hydrogen production. Therefore, exploitation of cost-effective electrocatalysts is essential to realize the industrialization of electrocatalytic techniques. In recent years, transition metal phosphides (TMPs) as non-noble metal electrocatalysts have gained a great deal of attention owing to their multifunctional active sites, tunable structure and composition, as well as unique physicochemical properties. However, the poor electrical conductivity of TMPs and high adsorption energy of hydrogen intermediates during the hydrogen evo-lution severely restrict its large-scale application. Therefore, it is of great importance to develop effective activity engineering to TMPs. Herein, the reaction mechanisms of water splitting including hydrogen evolution and oxygen evolution reactions and the key per-formance parameters are briefly clarified. Then, the strategies to improve the performance of TMPs are summarized in four aspects, including modulation of electronic structure, tailoring microstructures, selection of working electrode, and replacing OER with an energy-saving reaction. Finally, a summary and perspective for further opportunities and challenges are highlighted for the TMPs from the point of characterization methodologies, theoretical calculation and practical application.(c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.