Achieving High Electrocatalytic Efficiency on Copper: A Low-Cost Alternative to Platinum for Hydrogen Generation in Water

A phosphate mediated (photo)electro-reduction process has been developed to activate cuprous oxide (Cu2O) to copper–cuprous oxide (Cu/Cu2O) for high efficient hydrogen evolution reaction (HER) in water at neutral pH. The activated copper-based electrode can efficiently catalyze HER with an impressive onset potential of −30 mV vs reversible hydrogen electrode (RHE), low Tafel slope of 60–80 mV·decade–1 and exchange current density j0 of 3.0 × 10–5 A·cm–2. This represents the first highly active copper-based electrocatalyst that could be used as a low-cost alternative to Pt for water electrolysis.