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.