Biodiversity Benefits for Size Modulation of Metal Nanoparticles to Achieve In Situ Semi‐Oxidation toward Optimized Electrocatalytic Oxygen Evolution

Abstract Biodiversity endows similar species with subtle differences in composition, microstructure, and surface chemistry, making biomass a promising precursor to control the resulting active structure for heterocatalysis. Here, it is shown that Tremella fuciformis (Tfu), possessing an abundant porous structure and favorable metal affinity, is favorably serves as a precursor for confining uniform metal nanoparticles, by comparing the chemical characteristics of six varieties of agarics. The modest size of Co in the Tfu derived composite, Co@NPC‐Tfu (NPC = N, P co‐doped carbon), is suitable for in situ semi‐oxidation during oxygen evolution reaction (OER), forming a stable core‐shell structure of Co₃O₄@Co. Thus, Co@NPC‐Tfu can be used as a state‐of‐the‐art electrocatalyst for OER with an overpotential of 213.6 ± 4.1 mV at 10 mA cm⁻², and a significant turnover frequency of 3.21 s⁻¹ at 300 mV, benefitting from the optimum trade‐off between the atom utilization and electrical conductivity. Operando spectroscopy and theoretical calculations unveil the occupied state modulation of the robust carbon‐bonded PO_x groups, which optimizes the intermediate adsorption to accelerate OER kinetics. Moreover, Tfu derived Ni@NPC‐Tfu can be also prepared as a high‐performance hydrogen evolution reaction electrocatalyst, which can be utilized for efficient overall water splitting coupled with Co@NPC‐Tfu.