NiCoP/CoP sponge-like structure grown on stainless steel mesh as a high-performance electrocatalyst for hydrogen evolution reaction

8 figures, 2 tables.-- Supplementary information available.
The stainless steel mesh (SSM) has received remarkable attention for hydrogen and oxygen evolution reactions. It was demonstrated that the SSM exhibits admirable performance towards oxygen evolution reaction (OER) electrocatalysis, while its catalytic activity for hydrogen evolution reaction (HER) remains quite low. This obstructs the utilization of SSM-based catalysts for sustainable complete water electrolysis. In this study, a facile hydrothermal route followed by a phosphorization process was adopted to transform commercially available SSM materials into high-performance and stable electrocatalysts for alkaline HER. We report an interconnected NiCoP-CoP sponge-like structure on SSM substrate without polymer binder. Benefiting from the 3D construction with high exposed surface area, close contact between electroactive species and conductive surface, and facilitated infiltration of electrolyte, the as-prepared NiCoP@SSM electrocatalyst brought an improved catalytic activity for HER, required a low overpotential of 138 mV to derive a current density of 10 mAcm−2 in 1.0 M KOH aqueous solution. The high performance of the NiCoP@SSM catalyst has also unveiled fast reaction kinetics (presents a small Tafel slope of 74 mV/dec), a relatively large electrochemical active surface area (ECSA), and small charge transfer resistance. Furthermore, the NiCoP@SSM electrode also presented excellent stability during long-term measurements, making it one of the most encouraging HER electrodes to date. This research study paves the way for the development of HER-active electrocatalysts made from SSMs that are commercially available, low-cost, and highly active.
The authors wish to acknowledge the grants PID2020-115848RB-C21 and PID2020-115848RB-C22 funded by MCIN/AEI/10.13039/501100011033.