2D Ti₃C₂Tx MXene-Supported Graphitic Carbon-Nitride-Decorated Co₃O₄ Nanoparticles as Efficient Catalysts for Oxygen Evolution Reaction

Transition metal cobalt oxide (Co 3 O 4 ) with a typical spinel structure is considered a promising electrocatalyst for oxygen evolution reaction (OER). However, its OER catalytic performance is unsatisfactory owing to its limited activity. In this study, we demonstrate that using graphitic carbon nitride (g-C 3 N 4 ) loaded Co 3 O 4 nanoparticles and then anchoring them onto 2D Ti 3 C 2 Tx MXene with a layered structure can significantly enhance the OER catalytic performance. This performance may be due to the well-layered structure of g-C 3 N 4, thereby enabling it to provide more attachment sites for Co 3 O 4 nanoparticles, reducing their agglomeration properties and exposing more active sites to promote OER catalytic performance. When anchoring Co 3 O 4 @g-C 3 N 4 on Ti 3 C 2 Tx MXene, solid-state interfacial interactions can adjust the structure of electrons and promote the rate of interfacial charge transfer, which enhances the conductivity of the catalyst and further promotes its OER catalytic performance. The overpotential required for TCN is 247 mV at a current density of 10 mA cm –2, which is significantly lower than that of pure Ti 3 C 2 Tx MXene (600 mV) and Co 3 O 4 @g-C 3 N 4 (387 mV), in addition to exhibiting excellent electrochemical stability.