Tracking the role of compressive strain in bowl-Like Co-MOFs structural evolution in water oxidation reaction

Abstract

Dynamic structural evolution of catalyst active sites is crucial to for transition metal-catalyzed oxygen evolution reaction (OER). Yet, the elucidation of their mechanism behind the compressive-strain-induced reconstruction during OER process remains enigmatic. Here, we construct a bowl-like cobalt-based metal-organic frameworks (BL-Co-MOFs) catalyst with compressive strain to investigate the effect of strain on the structural evolution process and the OER mechanism. In situ techniques directly observe that compressive strain exists in the reconstruction of the potential-driven CoOOH-like active phase with contractile interatomic CoCo distance, promoting a direct OO radical coupling over the Co sites (Co−O−O−Co) during the OER process. This disrupts the constrains of the inherent linear scaling relationship and achieves the kinetic-faster oxide path mechanism (OPM) during OER process. Consequently, the BL-Co-MOFs exhibit a huge mass activity of 12516 A gmetal−1 and a large turnover frequency of 6888 h−1 at a low overpotential of 275 mV (300 mA cm−2).