Superior role of MXene nanosheet as hybridization matrix over graphene in enhancing interfacial electronic coupling and functionalities of metal oxide

A superior efficiency of MXene (Ti₃C₂) nanosheet as a hybridization matrix over graphene is evidenced by comparative investigation on uniformly-stacked MnO₂–Ti₃C₂ and MnO₂–reduced graphene oxide (rGO) nanohybrids. Density functional theory calculation and spectroscopic analyses demonstrate a stronger interfacial electronic coupling and greater charge transfer of polar MnO₂ with hydrophilic Ti₃C₂ nanosheet than with hydrophobic rGO one, which maximizes the hybridization effect with the conductive nanosheet. Also, hybridization with Ti₃C₂ nanosheet is more effective in enhancing the ion diffusivity and porosity of MnO₂ than that with strongly self-stacking rGO, which is attributable to weaker self-stacking tendency of Ti₃C₂. Due to these hybridization effects, the MnO₂–Ti₃C₂ nanohybrid delivers larger specific capacitance with improved rate performance than does the MnO₂–rGO nanohybrid, underscoring higher efficiency of MXene hybridization in improving electrode performance. This study clearly demonstrates that exfoliated MXene nanosheet can act as a superior hybridization matrix over rGO to explore strongly-coupled nanohybrids with improved energy-related functionality.