Multi-metallic electrocatalysts as emerging class of materials: opportunities and challenges in the synthesis, characterization, and applications

Nowadays, extensive efforts have been devoted to the fabrication and design of metalbased catalysts with high activity, selectivity, and stability. Theoretical and experimental investigations have empowered the construction of a variety of techniques to tune the catalytic efficiency of catalysts by monitoring their size, morphology, composition, and crystal structure. Multimetal catalysts (MMCs) provide a revolutionary synergistic effect between metals, which is a promising strategy to tune and enhance the catalysts' productivity and product selectivity. The purpose of this article is to familiarize readers with the most uptodate information regarding the synthesis and classification of MMCs. The key roles of MMCs electrocatalysts in a variety of applications such as CO2 conversion via electrochemical CO2 reduction reaction (ECO2RR), H2 evolution reaction (HER), O2 evolution reaction (OER), O2 reduction reaction (ORR), N2 reduction reaction (NRR), methanol oxidation reaction (MOR), ethanol oxidation reaction (EOR), formic acid oxidation reaction (FAOR), and urea oxidation reaction (UOR) are summarized. This review also addressed the challenges and prospects for multimetallic catalyst design, characterization, and applications. This review article will provide a clear roadmap for the research and progress of multimetallic catalysts for electrocatalytic applications.