Quenching-triggered amorphous/crystalline-heterostructure with tensile strain achieves efficient alkaline HER kinetics by operating the unique Co1–P–Co2 electrocatalytic mechanism

Abstract

Finding a feasible technique to introduce strain into phosphides to achieve Pt-like performance in the hydrogen evolution reaction (HER) is a challenge. This work innovatively adopted phosphorization–quenching technology to successfully construct CoOx/CoP-L nanosheets with an amorphous/crystalline (a/c)-heterostructure and 2.65% tensile strain. Strikingly, quenching also triggered a distorted lattice structure, promoting the exposure of active sites. Surprisingly, the well-designed CoOx/CoP-L needs only 56.6 mV and 98 mV to drive a current density of 10 mA cm⁻² for alkaline and acidic HER, respectively. Especially for alkaline HER, its performance exceeds that of Pt/C at high current density. Overall, this work provides a new design idea for transition-metal-based catalysts to optimize the catalytic mechanism of alkaline HER and achieve a performance surpassing that of Pt.