Ultrafine PtCoNi Intermetallics Stabilized within Ordered Mesoporous Carbon for Efficient Hydrogen Evolution Electrocatalysis

ABSTRACT Ordered intermetallic bimetals have offered wide application for hydrogen (H 2 ) production from hydrogen evolution reaction (HER) electrocatalysis, but commercial implementation is still slow than expected due to insufficient activity and stability. In this work, by alloying Ni atoms into intermetallic PtCo bimetals and being further stabilized into mesoporous carbon skeleton (i‐Pt 1 Co x Ni 1‐x @MC), the electrocatalyst disclosed remarkably high HER performance in a wide pH range. Mechanism studies revealed that alloying Ni in PtCo bimetals resulted in the electron‐deficient state of Pt sites, which optimized the H 2 O dissociation and facilitated H 2 coupling in Heyrovsky step for active and stable HER electrocatalysis. Compared to other counterpart electrocatalysts, trimetallic i‐Pt 1 Co x Ni 1‐x @MC disclosed the best performance in 1.0 M KOH, with a mass activity of 3.76 A mg −1 and a specific activity of 30.79 mA cm −2 at an overpotential of 100 mV. Meanwhile, high HER stability was also achieved for 5000 cycles with well‐retained structure and orderliness. The high performance of HER electrocatalysis in a wide pH range is expected to highlight practical application under harsh conditions.