Modulation of Electronic Structure in Multi‐Metal Prussian Blue Analogs to Enhance Electrocatalytic Oxygen Evolution Reaction

ABSTRACT The multimetallic synergy of multi‐metal catalysts (MMCs) endows them with outstanding catalytic performance towards oxygen evolution reaction (OER). Studies on OER electrocatalysis by using MMCs are primarily focused on the variation of transition metal composition. The electron structure in the kinetic behavior of MMCs has received little attention, let alone the control mechanisms of the electron structure modulation in kinetic behavior. In this work, we demonstrate a way to modulate the kinetic behavior by constructing the catalyst to obtain Ce‐based multi‐metal Prussian blue catalysts (CeMMPBA‐x, x = usage ratios of Ce/(Ce + Ni + Co + Zn)) through regulating various usage ratios of Ce/(Ce + Ni + Co + Zn). Experimental tests demonstrated that when the usage ratio of cerium nitrate to other nitrate metals was 2:1:1:1, CeMMPBA‐2 delivered an excellent electrocatalytic performance for OER, reaching 10 mA cm −2 with the potential at 1.49 V vs. RHE, respectively. Amazingly, CeMMPBA‐2 also realized a negligible loss of activity even after 12 h in stability tests. Characterization results indicated that cerium facilitated the electron transfer from Ce to Fe/Ni sites through its distinctive 4f/5d electronic configuration and redox activity, which did a favor for CeMMPBA‐2 to optimize the intermediate OH* adsorption, thereby enhancing its electrocatalytic ability to drive OER. This study gives new ideas on the design of multi‐metal electrocatalysts with high efficiency to induce electron strategies to achieve high‐entropy catalysts for energy conversion.