Adjusting surface electron density of heterostructured NiCo LDH/MXene/NF material to improve its electrocatalytic performance in hydrogen evolution reaction.

Hydrogen production by water electrolysis has attracted much interest in the field of renewable energy storage due to its high efficiency and low environmental impact. Catalytic activity of transition metal-based electrode materials can be effectively improved by adjusting their composition and/or structure. In this study, MXene nanosheets are electrophoretically deposited on foamed nickel (MXene/NF), and further coated by NiCo layered double hydroxides (LDH) nanosheets, also by electrophoresis, to obtain the heterostructured and highly conductive NiCo LDH/MXene/NF electrode, highly active in the hydrogen evolution reaction. Uniform surface distribution of three-dimensional interconnected nanosheets is demonstrated by SEM and TEM. The electrode surface is fully wet within 150 ms, indicating excellent hydrophilicity. The highly conductive NiCo LDH/MXene/NF electrode material exhibits a potential overshoot of 123 mV vs. RHE at a current density of 10 mA cm−2, with a Tafel slope of +86.6 mV dec−1. Long-term cyclic testing confirms good stability of the newly prepared electrode material in the hydrogen evolution reaction. • The abundant polar functional groups of MXene can also facilitate water adsorption. • Modulate the surface electron density of NiCo LDH/MXene/NF heterostructure by the Schottky effect. • MXene nanosheets were deposited onto NF via electrophoretic deposition. [ABSTRACT FROM AUTHOR]