Applications of MXene (Ti3C2Tx) in photocatalysis: a review

MXenes are two-dimensional nanomaterials, which can be constructed from different elements. The rich interlayer groups, surface groups, and the flexible layer spacing of MXenes make them ideal catalysts. Among these, Ti3C2Tx has gained particular attention as a photocatalyst for photocatalytic CO2 reduction reactions (CO2RR), hydrogen evolution reactions (HER), and photocatalytic degradation reactions. The structure of Ti3C2Tx, hydrophilic surface functional groups, and the Gibbs free energy for hydrogen adsorption lead to the excellent photocatalytic HER performance of this material. Numerous surface defects on Ti3C2Tx also provide plentiful CO2 adsorption sites for CO2RR. It is the structure of two-dimensional nanomaterials and their high-speed electron transport channels that enable their excellent catalytic oxidation activity. However, at present, there are still challenges that limit their further application, the most significant of which is the material stability. In order to overcome this, the synthetic routes to prepare these photocatalysts need to be adapted.