Abstract: One key step for advancing the widespread practical application of rechargeable metal-air batteries and water electrolysis fundamentally relies on the development of cost-effective multifunctional electrocatalysts toward oxygen and hydrogen-involving reactions. The present work initiates a tofu-derived one-pot strategy for green, facile, and mass production of highly active and stable catalyst toward oxygen reduction/evolution and hydrogen evolution reactions, through the preparation of Fe/Co cross-linked tofu gel and the subsequent pyrolysis. Despite the free use of additional N/P precursors or pore-forming agents, the as-prepared materials comprise highly dispersive FeCo-rich phosphides nanoparticles and porous N,P co-doped carbon network inherited from the tofu skeleton. The resultant catalysts exhibit remarkably enhanced trifunctional activities as compared to the Fe₂P and Co₂P counterparts, along with better long-term stabilities than the benchmark RuO₂ and Pt/C catalysts. Accordingly, the as-assembled Zn-air battery delivers a large power density (174 mW cm^-2) with excellent cycle stability (the gap of charge/discharge voltage@10 mA cm^-2 increases by 0.01 V after 720 h of operation, vs. 0.16 V of Pt/C-RuO₂ based battery after 378 h). Furthermore, the as-constructed alkaline electrolyzer just requires a small voltage of 1.55 V@10 mA cm^-2, which outperforms nearly all of those of biomass-derived electrocatalysts ever reported, and that of noble metal catalysts-based electrolyzers (1.72 V@10 mA cm^-2 for Pt/C-RuO₂), underscoring their bright future toward commercial applications in green energy conversion devices.

Key words: Soybean, Phosphides, Electrocatalysis, Overall water splitting, Zn-air battery