Self-Nanocavity-Confined Halogen Anions Boosting the High Selectivity of the Two-Electron Oxygen Reduction Pathway over Ni-Based MOFs

We present a strategy of self-nanocavity confinement for substantially boosting the superior electrochemical hydrogen peroxide (H2O2) selectivity for conductive metal-organic framework (MOF) materials. By using operando synchrotron radiation X-ray adsorption fine structure and Fourier transform infrared spectroscopy analyses, the dissociation of key *OOH intermediates during the oxygen reduction reaction (ORR) is effectively suppressed over the self-nanocavity-confined X-Ni MOF (X = F, CI, Br, or I) catalysts, contributing to a favorable two-electron ORR pathway for highly efficient H2O2 production. As a result, the as-prepared Br-confined Ni MOF catalyst significantly promotes H(2)O(2 )selectivity up to 90% in an alkaline solution, evidently outperforming the pristine Ni MOF catalyst (40%). Moreover, a maximal faradic efficiency of 86% with a high cumulative H(2)O(2 )yield rate of 596 mmol g(catalyst)(-1 )h(-1) for electrochemical H2O2 generation is achieved by the Br-confined Ni MOF catalyst.

Automated summary

The study presents a strategy of self-nanocavity confinement to boost the electrochemical H2O2 selectivity for conductive metal-organic framework (MOF) materials. The Br-confined Ni MOF catalyst achieves significantly higher H2O2 selectivity and efficiency in an alkaline solution, outperforming the pristine Ni MOF catalyst.