Self-supporting sandwich-structured Co–Pt–Co/CC electrocatalysts for high effective hydrogen production by electrolysis of water in alkaline solution

Trace precious metal modifying inexpensive transition metal catalyst is an effective method to optimize the activity, stability and cost of hydrogen evolution catalysts. In this feature work, self-supporting sandwich structured Co–Pt–Co/CC sheets were assembled on a carbon cloth (CC) by a simple electrodeposition/chemical displacement alternate growth method. Surprisingly, only 2.1 wt % Pt sandwich layer greatly improved the electrochemical activity of Co–Pt–Co/CC, which delivered a current density of 10 mA cm −2 at an overpotential as low as 46 mV. Importantly, its overpotential is almost 6 times lower than that of Co/CC, and is comparable to that of Pt–Co/CC. After well-tuning the sandwich layer, the optimized Co–Pt–Co/CC exhibited a higher current density and better long-term durability compared with Pt–Co/CC and Co/CC, which can be attributed to the unique tissue-structure and electronic structure optimization of the Co–Pt–Co/CC by the Pt sandwich layer.