Tailoring 2-electron oxygen reduction reaction selectivity on h-BN-based single-atom catalysts from superoxide dismutase: A DFT investigation

Abstract

The production of hydrogen peroxide (H2O2) plays an important role in human lives. Currently applying the two-electron oxygen reduction reaction (2e- ORR) to synthesis of H2O2 is regarded as a promising strategy to substitute the traditional anthraquinone method;however, design of efficient 2e- ORR catalysts remains difficulties. Inspired by superoxide dismutase, which can covert superoxide (•O2–) to H2O2. We design eight types of 2e- ORR catalysts in which Ni is embedded on defective boron nitride (h-BN) which coordinates with non-metal atoms (B, N, O, S) doping to imitate the active center of superoxide dismutase. Density functional theory (DFT) computations demonstrate that NiN2S2/BN has the most favorable 2e- ORR catalytic performance with the overpotential of 0.11 V. Especially, the competitive 4e- ORR pathway can be significantly suppressed, as indicated by favorable thermodynamics with more positive Gibbs free energies of O* above 3.52 eV. Besides, coordination environments change induced different adsorption behavior of O2, electron density around Ni, and work function are unveiled. Our work is expected to provide useful understanding for development of novel high-efficiency h-BN-based single-atom catalysts for 2e- ORR.