A review of modulation strategies for improving catalytic performance of transition metal phosphides for oxygen evolution reaction

Recently, researchers have focused on non-noble metal catalysts to replace noble metal catalysts for oxygen evolution reaction that is crucial for hydrogen production from water splitting. Among many metal-based compounds, transition metal phosphides (TMPs) often exhibit excellent HER catalytic performance due to the high electronegativity of P, which is favored by researchers. However, the OER catalytic performance of TMPs is not outstanding. Thus, improving its OER catalytic performance is crucial for the realization of excellent overall water-splitting bifunctional TMPs catalysts. In this review, we take TMPs as an example to analyze how to prepare highly active OER catalysts. Firstly, the evaluation criteria of OER reaction are introduced to compare the activity of catalysts. Then, from two aspects of improving the intrinsic activity of active sites and increasing the number of active sites/active surface area, we analyzed how to prepare highly active OER catalysts. For the former, it is often necessary to explore the method to make the OER potential close to the thermodynamic limit on the basis of understanding the OER mechanism. Therefore, we first summarized the widely recognized OER mechanism. Then, in order to improve the intrinsic activity of active sites, this paper expounds how to prepare efficient OER catalysts from four aspects: optimizing the adsorption and desorption of key intermediates, generating and optimizing vacancies in the catalyst, building multiple active sites, and promoting the formation of active phases. These four aspects are in line with the mechanism one by one; To increase the number of active sites/active surface area, strategies for constructing unique nanostructures and selecting special carriers were proposed. Finally, we propose key issues and challenges for future development in view of the shortcomings of each method.