Boride and borate based electrocatalysts for electrochemical oxidation reactions: recent advances, mechanistic insights, and future perspectives.

The development of highly effective and robust electrocatalysts is vital for advancing sustainable hydrogen production and energy conversion technologies. Among the emerging catalyst families, boride and borate-based electrocatalysts have emerged as promising materials for sustainable electrochemical oxidation reactions because of their high electrical conductivity, tunable electronic structures, abundant active sites, and excellent corrosion resistant nature. These materials exhibit outstanding performance in the oxygen evolution reaction (OER) and alternative anodic oxidation reactions, including electrochemical oxidation reactions of small molecules undergoing decomposition at very low energy. The significance of boride/borate based electrocatalysts is particularly evident in direct seawater electrolysis, where chloride-induced corrosion and the challenging chlorine evolution reaction (CER) hinder practical implementation. Borate species play a multifunctional role by promoting active surface reconstruction, stabilizing catalytic sites, suppressing chloride adsorption and the CER, buffering the local reaction environment, and enhancing OER selectivity and durability. Boride and borate-based materials also enable energy-efficient hydrogen production and value added chemical production using the urea oxidation reaction (UOR), glucose oxidation reaction (GOR), hydrazine oxidation reaction (HzOR), alcohol oxidation reaction (AOR), and biomass oxidation reaction (BOR) as anodic reactions. This review elaborately discusses recent advances in boride and borate-based electrocatalysts, highlighting structure-activity relationships, interfacial engineering, and the unique characteristics of borate as a corrosion inhibitor and chloride-resistant layer for effective seawater electrolysis. Finally, the key challenges and future opportunities for developing durable, selective, and industrially feasible boride/borate-based electrocatalysts for effective hydrogen production are discussed.