Strong d‐p Orbital Hybridization of Os‐P via Ultrafast Microwave Plasma Assistance for Anion Exchange Membrane Electrolysis

Abstract Orbital hybridization is a promising approach to modulating the electronic structure of the designed electrocatalysts to boost reaction kinetics. In contrast to d‐d hybridization, p‐d orbital hybridization between p‐block elements and d‐block metals can provide new opportunities to modulate the electronic properties and thus promote the catalytic performance. Herein, a phosphorus‐doped osmium (P‐Os) catalyst is designed through ultrafast (20 s) microwave plasma engineering. Theoretical calculations verify the d‐p orbital hybridization between P and Os, leading to the modulation of the d‐band center of the Os active site. Specifically, P neighboring Os exhibit the highest catalytic activity, facilitating crucial processes such as H₂O/H* adsorption and dissociation. The overpotential of P‐Os in alkaline seawater is only 152 mV at 1 A cm⁻², which is superior to the reported seawater electrocatalysts. Moreover, the synthesized P‐Os catalysts are integrated into an anion exchange membrane (AEM) electrolyzer, demonstrating remarkable performance. The AEM electrolyzer requires 1.86/2.02 V to achieve 500/1000 mA cm⁻² current densities. Then, the achieved P‐Os have great potential for practical electrocatalytic water‐splitting applications.