A robust hydrogen evolution catalyst based on crystalline nickel phosphide nanoflakes on three-dimensional graphene/nickel foam: high performance for electrocatalytic hydrogen production from pH 0–14

Abstract

The design and preparation of highly active catalysts for the hydrogen evolution reaction (HER) is very important for water splitting. Herein, we report a highly active HER catalyst, which is synthesized by loading nanostructured nickel phosphide (Ni₂P) on three-dimensional few-layer graphene/nickel foam (G@NF). G@NF was successfully prepared by a chemical vapor deposition process in the presence of methane at high temperature. Compared with nickel phosphide, G@NF, as well as commercial platinum, the Ni₂P–G@NF catalyst exhibited very high activity in electrocatalytic H₂ production from water (∼7 mV overpotential in alkaline solutions, pH ∼ 14; and ∼30 mV overpotential in acidic solutions, pH ∼ 0). The high catalytic activity of Ni₂P–G@NF is attributed to the excellent performance of Ni₂P, the large 3D framework which facilitates proton accessibility and electron transfer, and the high surface area.