3D-Printed Hierarchical Nanostructured N-CoNiO NF Electrode for Efficient Concurrent Electrocatalytic Production of Hydrogen and Formate.

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 CoNiO nanoflakes (N-CoNiO NF) is proposed for efficient electrocatalytic oxidation of glycerol to formate. The synergistic effect induced by the interaction of the layered CoNiO nanostructures on the 3D-printed Nickel-Yttria-stabilized zirconia (Ni-YSZ) substrate and the amorphous nitrogen-doping promotes the anodic GER. The N-CoNiO NF exhibits low potentials of 1.07 and 1.18 V (vs. RHE) for GER to drive 10 and 50 mA cm, respectively. The constituted two-electrode electrolyzer (N-CoNiO 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, 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.