Ni-Doped\nCu Oxide Catalysts for ORR: Suppressing H<sub>2</sub>O<sub>2</sub> Formation By Engineering Chemical Strain

Ni-doped copper oxide (Cu[Ni]O<sub><i>x</i></sub>/Au)\nhas demonstrated considerable promise toward efficient oxygen reduction\nreaction (ORR) under alkaline conditions. The Cu-rich samples like\nCu<sub>0.8</sub>Ni<sub>0.2</sub>O<sub><i>x</i></sub>/Au\nshow better activity and selectivity than benchmarks such as Pt and\nAu, exhibiting H<sub>2</sub>O<sub>2</sub> yields <5% throughout\na sizable potential range. The electrode’s performance did\nnot degrade even under 3000 potential cycles under ORR conditions.\nIn situ Raman spectroscopy indicated a Cu-O-Ni type framework where\nNi doping into CuO<sub><i>x</i></sub> results in coordinatively\nunsaturated Ni centers within the Cu-O-Ni framework. These centers\nare active toward easier cleavage of O–O bonds resulting in\nan overall preference for the 4e pathway for O<sub>2</sub> reduction\nto H<sub>2</sub>O.