Catalysis

Oxygen evolution

Engineering

Electrochemistry

Materials science

Chromatography

Water splitting

Polymer electrolyte membrane electrolysis

Nanosheet

Inorganic chemistry

Chemical engineering

Electrolysis of water

Physical chemistry

Hydrogen

Nanotechnology

Organic chemistry

Alkaline water electrolysis

Cobalt

Chemistry

Electrode

Anode

Photocatalysis

Hydrogen production

Electrolyte

Electrolysis

Hydrazine (antidepressant)

Bifunctional

Angewandte Chemie International Edition

Water electrolysis is a promising source of hydrogen; however, technological challenges remain. Intensive efforts have focused on developing highly efficient and earth‐abundant electrocatalysts for water splitting. An effective strategy is proposed, using a bifunctional tubular cobalt perselenide nanosheet electrode, in which the sluggish oxygen evolution reaction is substituted with anodic hydrazine oxidation so as to assist energy‐efficient hydrogen production. Specifically, this electrode produces a current density of 10 mA cm −2 at −84 mV for hydrogen evolution and −17 mV for hydrazine oxidation in 1.0 m KOH and 0.5 m hydrazine electrolyte. An ultralow cell voltage of only 164 mV is required to generate a current density of 10 mA cm −2 for 14 hours of stable water electrolysis.

Anodic Hydrazine Oxidation Assists Energy‐Efficient Hydrogen Evolution over a Bifunctional Cobalt Perselenide Nanosheet Electrode