Theoretical and experimental design of Pt-Co(OH)2 electrocatalyst for efficient HER performance in alkaline solution

Design efficient electrocatalysts become significant for the hydrogen evolution reaction (HER) in alkaline solution. Here, the HER performance on Pt-Co(OH)2 has been investigated by using DFT calculations. Compared with pure Pt, the Pt-Co(OH)2 shows excellent hydrogen binding energy (−0.29 eV) and hydrogen adsorption free energy (0.02 eV). More strikingly, the water dissociation process on Pt-Co(OH)2 is an exothermic reaction while that of Pt is an endothermic reaction, demonstrating that the Pt-Co(OH)2 is an excellent catalyst for HER in alkaline medium. Then the two-step electrodepositions was used to fabricate Pt-Co(OH)2 on the carbon paper (CP). The Pt-Co(OH)2/CP shows the lowest overpotential of only 37.6 mV at a current density of 10 mA cm−2 in 0.1M KOH, the smallest Tafel slope of 58 mV dec−1 and the good stability for 20000s without obvious degradation.