Anchoring MoS₂ on an ethanol-etched Prussian blue analog for enhanced electrocatalytic efficiency for the oxygen evolution reaction

Controllable defects and interface engineering are promising routes for developing efficient noble-metal-free electrocatalysts for the oxygen evolution reaction (OER), the bottleneck of overall water splitting. Herein, we prepared molybdenum disulfide (MoS₂)-decorated hollow nanoframes of a Co-Fe Prussian blue analog (Etched-PBA-MoS₂) by mild chemical etching of the Co-Fe Prussian blue analog (PBA) nanocubes, followed by MoS₂ decoration. We propose using an ethanol-water mixture as a mild etchant, eliminating the need for a capping or stabilizing agent. Prominently benefiting from the enhanced active surface area and the synergistic effect of multi-components, the as-prepared Etched-PBA-MoS₂ nanoframes deposited on a microporous carbon cloth could deliver an excellent OER activity with an overpotential of only 260 mV to obtain a current density of 10 mA cm⁻² with a Tafel slope of 55 mV dec⁻¹ in 1.0 M KOH. This work provides a protocol to rationally design PBA-based heterostructures for inexpensive electrocatalysts.