Multiscale Hierarchical Structured NiCoP Enabling Ampere-Level Water Splitting for Multi-Scenarios Green Energy-to-Hydrogen Systems

Efficient and stable low-cost catalysts are seriously lacking for industrial water electrolysis at large-current-density. To meet industrial-scale hydrogen production, fully utilized active sites by a rational structure design is an attractive route. Herein, dynamic microstructure manipulation of bimetallic phosphide NiCoP is conducted. Among different microstructures for NiCoP, as-obtained NiCoP-120 at hydrothermal temperature of 120 degrees C, shows a special multiscale hierarchical structure from 3D-nickel foam substrates, 2D-nanosheets to 1D-nanoneedles, which is conducive to efficient utilization of active sites and rapid gas release, thus manifesting outstanding electrocatalytic activities and stability as required by industry. To reach a current density of 10 and 1000 mA cm(-2) for the hydrogen evolution reaction (HER), NiCoP-120 requires ultra-low overpotentials of 56 and 247 mV, respectively. Particularly, as a bifunctional catalyst, it only needs 1.981 V to drive the 1 A cm(-2) overall water splitting and can maintain stable output for 600 h, which is superior to almost all reported non-noble metal catalysts. Moreover, its application prospect in integrated green energy-to-hydrogen systems, including sunlight, wind, thermal, and lithium cells, is well demonstrated. This work provides a guiding strategy for the design of industrial water electrolysis catalysts and the establishment of an externally driven water-splitting hydrogen production system.

Automated summary

Efficient and stable low-cost catalysts are lacking for industrial water electrolysis. This work demonstrates the dynamic microstructure manipulation of bimetallic phosphide NiCoP, which enables efficient utilization of active sites and stability as required by industry.