Innovative Catalyst Design of Sea-Urchin-like NiCoP Nanoneedle Arrays Supported on N-Doped Carbon Nanospheres for Enhanced HER Performance.

Hydrogen (H 2 ) stands as a clean energy alternative to fossil fuels, especially within the domain of the hydrogen evolution reaction (HER), offering prospective solutions to mitigate both environmental and energy-related challenges. In this work, we successfully synthesized a sea-urchin-like catalyst, specifically a nickel-cobalt phosphide nanoneedle array on N-doped carbon nanospheres (Ni 0.5 Co 1.5 P@NCSs), for efficient HER by a sequential hydrothermal and low-temperature phosphating process. The catalyst exhibits sea-urchin-like structures, offering a specific surface area of 298 m 2 g -1 and consequently furnishing a greater abundance of active sites. Comparing with non-sea-urchin-like Ni 0.5 Co 1.5 P@CN catalysts, the Ni 0.5 Co 1.5 P@NCSs exhibit an overpotential of 163 mV at 10 mA cm -2 , a Tafel slope of 60 mV dec -1 , and a maintained current density of approximately 90% during 50 h of continuous electrolysis. Experiments demonstrate that the outstanding electrochemical properties of the Ni 0.5 Co 1.5 P@NCSs originate from nitrogen doping of carbon spheres, the distinctive morphology of sea-urchin-like nanoneedle arrays, and simultaneous enhancements in intermediate adsorption energy, charge transfer, and electrolyte diffusion channel shortening. This work emphasizes a preparation strategy for synthesizing an attractive electrocatalyst with a low cost and efficient HER performance.