posted on 2021-09-02, 15:42authored byMeihuan Liu, Yuanli Li, Zeming Qi, Hui Su, Weiren Cheng, Wanlin Zhou, Hui Zhang, Xuan Sun, Xiuxiu Zhang, Yanzhi Xu, Yong Jiang, Qinghua Liu, Shiqiang Wei
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, Cl, 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 H2O2 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 H2O2 yield rate of 596
mmol gcatalyst–1 h–1 for electrochemical H2O2 generation is achieved
by the Br-confined Ni MOF catalyst.