Development of highly efficient and
stable non-precious
metal-based
pH-universal catalysts for hydrogen evolution reaction (HER) at high
current densities remains challenging for water electrolysis-based
green hydrogen production. Herein, a simple solvothermal process was
developed to synthesize a NiMo metal–organic framework (MOF),
from which a carbon-armored Ni4Mo alloy of an interwoven
nanosheet structure was derived with a two-stage thermal treatment,
to serve as a high-performance pH-universal HER catalyst. It requires
low overpotentials of 22, 48, and 98 mV to achieve a current density
of −10 mA cm–2 and 192, 267, and 360 mV to
deliver an ultrahigh current density of −500 mA cm–2 in alkaline, acidic, and neutral media, respectively, and exhibits
remarkable operational stability at an ultrahigh initial current density
of −500 mA cm–2 for over 50 h, making it
promising for applications in large-scale green hydrogen production.
The success can be attributed to the unique catalyst design of a carbon-armored,
composition-optimized NiMo alloy of an advantageous nanostructure
of interwoven nanosheets for enhanced utilization of active sites
and mass transfer of electrolytes and gaseous products, made possible
with a MOF-derivation fabrication approach.