Highly efficient C@Ni-Pd bifunctional electrocatalyst for energy-saving hydrogen evolution and value-added chemicals co-production from ethanol aqueous solution

Energy-saving electrolytic hydrogen production could be realized by replacing sluggish oxygen evolution reaction (OER) with ethanol oxidation reaction (EOR). However, it's challenging to obtain high-performance electrocatalysts with excellent activity (close to the theoretical potential for EOR), superior production selectivity, and stability (anti-poisoning during EOR). In this study, a C@Ni-Pd bifunctional catalyst is fabricated towards EOR and hydrogen evolution with high activity, selectivity, and stability. The potential of EOR over the C@Ni-Pd catalyst is reduced by 1.072 V relative to OER at 100 mA cm−2. In the water–ethanol co-electrolysis device, the onset potential is as low as 0.4 V, and the current density reaches 100 mA cm−2 at 0.95 V. The power consumption of device is still lower than the water electrolysis theory at high current density. High-selective acetate could be co-produced with hydrogen while without CO2 emission over C@Ni-Pd bifunctional catalysts. DFT and in-situ Raman spectroscopy results indicate that the highly-active Pd sites endow significant energy-saving hydrogen production effect. The high selectivity is derived from the abundant OH* on the surface of Ni, which promotes the conversion of *CH3CO adsorbed on Pd to *CH3COOH. This study provides a new straight to design high-performance electrocatalysts for energy-saving co-generation of pure hydrogen and value-added chemicals from organic fuels and water while without CO2 emissions.