Hollow carbon sphere-supported Pt/CoO hybrid with excellent hydrogen evolution activity and stability in acidic environment

Electrocatalytic hydrogen evolution reaction (HER) in acidic solution using Co-based oxides is extremely difficult due to their instability. Herein, we report a hollow carbon sphere-supported Pt/CoOx (Pt/CoOx-HCS) electrocatalyst for active HER in 0.5 M H2SO4 solution. Microstructural and electrochemical evaluations confirm the dissolution of major Co3O4 in Pt/Co3O4-loaded HCS (pre-Pt/Co3O4-HCS) and the steady existence of remaining CoOx in Pt/CoOx-HCS after 3000 cyclic voltammetry (CV) cycles (Pt/CoOx-HCS-3000). The Pt/CoOx-HCS-3000 exhibits a pretty high turnover frequency (TOF) of 24.87 H2 s−1 at 100 mV overpotential, a low overpotential of 28 mV at 10 mA cm−2, and a large mass activity of 3.59 A mgPt−1 at 30 mV overpotential. The robust stability of Pt/CoOx-HCS-3000 is attributed to the strong electronic interaction between Pt and CoOx, preventing the aggregation of the former and the thorough dissolution of the latter. This work provides insights into the design of Co based-oxide electrocatalysts with outstanding acidic performances.