Low-Coordinated Conductive ZnCu Metal-Organic Frameworks for Highly Selective H2O2 Electrosynthesis

Small. 2024 May 21:e2403808. doi: 10.1002/smll.202403808. Online ahead of print.

Abstract

Direct electrosynthesis of hydrogen peroxide (H2O2) with high production rate and high selectivity through the two-electron oxygen reduction reaction (2e-ORR) offers a sustainable alternative to the energy-intensive anthraquinone technology but remains a challenge. Herein, a low-coordinated, 2D conductive Zn/Cu metal-organic framework supported on hollow nanocube structures (ZnCu-MOF (H)) is rationally designed and synthesized. The as-prepared ZnCu-MOF (H) catalyst exhibits substantially boosted electrocatalytic kinetics, enhanced H2O2 selectivity, and ultra-high Faradaic efficiency for 2e-ORR process in both alkaline and neutral conditions. Electrochemical measurements, operando/quasi in situ spectroscopy, and theoretical calculation demonstrate that the introduction of Cu atoms with low-coordinated structures induces the transformation of active sites, resulting in the beneficial electron transfer and the optimized energy barrier, thereby improving the electrocatalytic activity and selectivity.

Keywords: conductive metal‐organic frameworks; hollow structures; low‐coordinated metal site; two‐electron oxygen reduction reaction.