PtCo/Co Composite Catalysts on Porous N-Doped Carbon Support Derived from ZIF-67 with Enhanced HER and ORR Activities.

The primary challenge for efficient H evolution and hydrogen energy conversion is to develop highly active and stable catalysts with simple and reliable preparation processes. In this regard, we have designed and synthesized a porous carbon-supported low-Pt alloy catalyst (PtCo/Co@C composite) using ZIF-67 as a template. It showed uniformly dispersed PtCo/Co on the porous carbon layer due to the confinement effect of the porous carbon layer. PtCo/Co@C demonstrated excellent activity for the hydrogen evolution reaction in the full pH range, with an overpotential of 187 mV in 0.5 M HSO to attain 100 mA/cm as well as long-term stability. It also displayed superior mass activity for the oxygen reduction reaction (ORR) at 0.85 V (vs RHE) compared to the commercial Pt/C. Furthermore, the PtCo/Co@C catalyst exclusively enabled a four-electron reaction process under ORR conditions without the competitive pathway to HO. The current work provides guidance for the design and facile synthesis of Pt-based catalysts with enhanced performance.