Promotion of MXene (Ti3C2Tx) as a robust electrocatalyst for oxygen evolution reaction via active sites of ZIF-67 - In situ mechanism investigations

Developing a robust and highly efficient electrocatalyst for the oxygen evolution reaction (OER) is required, due to its sluggish mechanism and high overpotential. Here, we present the Ti3C2Tx and ZIF-67 composites (MXene/ZIF-67) for an efficient OER. The MXene/ZIF-67_1:10 exhibits an overpotential of 366 mV, which is better than MXene (548 mV) and RuO2 (395 mV). Moreover, it shows improved electrochemical stability at 20 mA·cm− 2 with only a 0.2% increase in potential after 5 h, while RuO2 with an overpotential loss of 3.5%. After an increase in the current density of 10–20 mA cm−2 the potential increase by 7.4%, while in RuO2 by 25.3%. To reveal the observed performance, the composite's robustness and explain each component's role. Moreover, a detailed OER mechanism is discussed. It was realized via in situ Raman microscopy and XRD which allowed the revealing of the active species responsible for boosting OER.