CsPbBr3 nanocrystals supported on partially oxidized Ti2N MXenes for photothermal CO2 conversion

Abstract

The development of new photo-thermal catalysts for the transformation of CO2 into fuels is of great interest, offering a clean and sustainable approach to reducing the carbon footprint. Herein, we present a novel hybrid material composed of nanocrystalline metal halide perovskite (CsPbBr3) supported on two-dimensional titanium nitride (Ti2N) MXene. Additionally, we demonstrate the importance of forming an external TiO2 layer through partial oxidation of the MXene (POM-Ti2N), which introduces catalytic centers and enhances photogenerated charge separation. Remarkable activity in the formation of CH4 and CO was observed, with yields of 321 µmol·g-1 and 480 µmol·g-1, respectively. The selectivity of the reaction was found to be temperature dependent. The mechanism was thoroughly investigated using XPS and photoluminescence studies. XPS analysis revealed a significant chemical interaction between the CsPbBr3 nanocrystals and the POM-Ti2N MXene after the formation of the composite. Photoluminescence measurements revealed a considerably shorter emission lifetime for the hybrid catalyst (τave = 1.73 ns) compared to that of the CsPbBr3 nanoparticles (τave = 25.32 ns), indicating strong interaction with the MXene. Furthermore, this research highlights the potential of combining metal halide perovskites with MXenes and the importance of controlling their interface for photo-thermal reactions.