Tailoring the d-band center of Ni on a dual-single-atom Ni-ZnNC catalyst for efficient H2O2 production

Electrocatalytic oxygen reduction reaction (ORR) for H2O2 production presents an alternative approach suitable for on-site applications. Although atomically dispersed earth-abundant metal species anchored in a nitrogen-doped carbon framework (M-N-C) have demonstrated significant 2e- ORR activity, the Ni-N-C catalyst exhibits unfavorable catalytic activity. It is well-recognized that the d-band center of the metal can be tailored by introducing transition metals, thereby altering the adsorption free energy of the OOH* reactive species. Herein, we have designed a dual-single-atom configuration (Ni-ZnNC), where the Zn atom serves as a modulator to adjust the d-band electronic energy of the Ni center, ultimately optimizing the intermediate adsorption and resulting in high 2e- ORR performance. The Ni-ZnNC catalyst demonstrates an H2O2 production rate of 5.6 mol/g/h at 0.0 VRHE with a notable H2O2 selectivity of approximately 60% in an acid electrolyte. Density-functional theory calculations reveal that the Zn atom effectively alters the d-band electronic energy of the Ni center, strengthening the Ni-OOH* binding affinity and thereby enhancing the adsorption process. This work provides valuable insights into the design of earth-abundant metal Ni-based electrocatalysts for H2O2 generation.(c) 2023 Elsevier Ltd. All rights reserved.