Laser-Assisted Doping and Architecture Engineering of Fe₃ O₄ Nanoparticles for Highly Enhanced Oxygen Evolution...

The design and synthesis of cost-effective and highperformance oxygen evolution reaction (OER) electrocatalysts for water splitting based on earth-abundant elements is urgent but challenging. A synergistic doping and architecture engineering strategy by nanosecond laser ablation is used to generate a unique kind of highly disordered Ni-doped Fe₃ O₄ nanoparticle clusters. Ni dopant and increased oxygen vacancies are simultaneously incorporated into Fe₃ O₄ frameworks and thereby modulate the electronic configuration for an optimal binding affinity towards OER intermediates. Nanoparticles with average size of around 5 nm assemble randomly during laser ablation and construct a fluffy and porous architecture, which not only optimizes the number of exposed active sites but also accelerates mass transfer. Consequently, Ni-doped Fe₃ O₄ clusters are revealed as a superior OER catalyst with a small overpotential of 272 mV at 10 mA cm^-2 and a small Tafel slope of 39.4 mV dec^-1 , surpassing almost all spinel Fe-based OER catalysts. This work provides a new strategy to fabricate advanced cation-doped metal oxide nanostructures for related energy applications.