Surface Roughed and Pt-Rich Bimetallic Electrocatalysts for Hydrogen Evolution Reaction

Platinum-based alloys with low cost transition metals have been considered as promising electrocatalysts in the field of sustainable energy conversion and storage. Herein, chloroplatinic acid, cobalt chloride, and carbon nanotubes are used as platinum, cobalt precursors, and carriers, respectively, to prepare rich Pt dealloying PtCo nanoparticles (SD-PtCo/CNT) via co-liquid phase reduction and chemical dealloying methods. The characterization and test results confirm that PtCo alloy nanoparticles are evenly dispersed on carbon nanotubes, further dealloying and resulting in the partial dissolving of cobalt, simultaneously generating a rich Pt layer and roughly active surface. Benefiting from the unique structure, the SD-PtCo/CNT catalyst displays obviously enhanced HER activity in both acidic and alkaline conditions. In 1.0 M KOH, SD-PtCo/CNT exhibits a low overpotential of 78 mV at 10 mA/cm² and a small tafel slope (38.28 mV/dec). In 0.5 M H₂SO₄, SD-PtCo/CNT still shows the superior performance compared with un-dealloying PtCo/CNT, with an overpotential of 17 mV at 10 mA/cm² and corresponding tafel slope of 21.35 mV/dec. The high HER activity of SD-PtCo/CNT can be attributed to the formation of a platinum rich layer and the uniformly dispersed PtCo nanoparticles supported on superior conductive carbon nanotubes, suggesting its great potential for hydrogen generation via water splitting.