Hierarchical Microspheres Composed of Mn-Doped CoP Nanosheets for Enhanced Oxygen Evolution

The efficiency of water splitting technology was largely limited by the sluggish catalyzed oxygen evolution reaction (OER). In this study, we found that construction of hierarchical nanostructures and heteroatom doping are two effective strategies to enhance the catalytic properties of transition-metal phosphides (TMPs) toward alkaline OER. We successfully synthesized a heteroatom Mn-doped CoP catalyst (denoted as Mn-CoP), which presents hierarchical microspheres assembled with porous nanosheets, through sequential solvothermal, thermal annealing in air, and chemical vapor deposition (CVD) processes. The doping of Mn can simultaneously regulate the morphology of the hierarchical microsphere nanostructure and modulate the electron structure of CoP. Remarkably, only 285 mV overpotential was needed to reach 10 mA cm(-2) of the Mn-CoP catalyst in alkaline conditions, largely outperforming the commercial RuO2 (330 mV). Besides, during the continuous 50 h chronoamperometry test, the Mn-CoP catalyst exhibits great stability and robustness. In short, this study provides a facile solution for designing and achieving high-efficiency and cost-effective nano-electrocatalysts in water splitting.