3D‐Printed Hierarchical Nanostructured N‐Co₂NiO₄ NF Electrode for Efficient Concurrent Electrocatalytic Production of Hydrogen and Formate

Abstract

Replacing the oxygen evolution reaction with the alternative glycerol electro‐oxidation reaction (GER) provides a promising strategy to enhance the efficiency of hydrogen production via water electrolysis while co‐generating high‐value chemicals. However, obtaining low‐cost and efficient GER electrocatalysts remains a big challenge. Herein, a self‐supported N‐doped Co2NiO4 nanoflakes (N‐Co2NiO4 NF) is proposed for efficient electrocatalytic oxidation of glycerol to formate. The synergistic effect induced by the interaction of the layered Co2NiO4 nanostructures on the 3D‐printed Nickel‐Yttria‐stabilized zirconia (Ni‐YSZ) substrate and the amorphous nitrogen‐doping promotes the anodic GER. The N‐Co2NiO4 NF exhibits low potentials of 1.07 and 1.18 V (vs. RHE) for GER to drive 10 and 50 mA cm−2, respectively. The constituted two‐electrode electrolyzer (N‐Co2NiO4 NF//NiS‐Co‐NiP) displays excellent activity that only requires ultralow cell voltages of 1.24 and 1.55 V to afford 10 and 200 mA cm−2, respectively, with a high FE (97%) for formate production and an excellent durability (120 h). This study provides a versatile approach for manufacturing high‐performance Ni‐based electrocatalyst for GER, paving the way for the energy‐saving and environmentally‐friendly co‐production of value‐added chemicals and hydrogen.