Highly Efficient and Self-Standing Nanoporous NiO/Al₃Ni₂ Electrocatalyst for Hydrogen Evolution Reaction

Low cost and highly efficient non-noble metal electrocatalysts for hydrogen evolution reaction (HER) are crucially important for the commercial production of hydrogen. In the present work, we prepared a nanoporous NiO/Al₃Ni₂ catalyst using a facile electrochemical dealloying method. Due to the large surface area, fast gas releasing, and the synergistic effects of NiO and Al₃Ni₂, the nanoporous NiO/Al₃Ni₂ catalyst exhibits remarkable HER activity with the overpotential of 66 mV at a current density of 10 mA cm^-2 and good long-time stability in alkaline conditions. The nanoporous NiO/Al₃Ni₂ catalyst has higher current density than the commercial Pt/C under high overpotential over 105 mV. Ni sites on the exposed active (100) surface of Al₃Ni₂ exhibit a moderate hydrogen adsorption energy. NiO effectively promotes water splitting and prevents intermediate poisoning on the Al₃Ni₂ active sites. Al₃Ni₂ improves the conductivity of the catalyst. This work provides a guidance for the design and development of non-noble HER electrocatalysts.