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 Ti 3 C 2 T x 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 RuO 2 (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 RuO 2 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 RuO 2 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. • MXene/ZIF-67 composite was designed for OER. • MXene/ZIF-67 presented outstanding electrocatalytic activity in OER. • MXene/ZIF-67 structures exhibit robust stability at high current density for a long time. • In situ Raman and XRD were applied to revile the mechanism of OER. [ABSTRACT FROM AUTHOR]