A retrospective on MXene-based composites for solar fuel production

MXene with two-dimensional layered structure and desirable electronic properties has emerged as a promising candidate to construct MXene-based composites towards various photocatalytic applications. As compared to the downhill-type photodegradation reactions, artificial photosynthesis often involves thermodynamic uphill reactions with a large positive change in Gibbs free energy. Recent years have witnessed the effectiveness of MXene in enhancing the photoactivity of MXene-based composites for solar fuel synthesis. In this review, we mainly focus on the applications of MXene-based composites for photocatalytic solar fuel production. We will start from summarizing the general synthesis of MXene-based composite photocatalysts. Then the recent progress on MXene-based composite photocatalysts for solar fuel synthesis, including water splitting for H2 production, CO2 reduction to solar fuels, and N2 fixation for NH3 synthesis is elucidated. The roles of MXene playing in improving the photoactivity of MXene-based composites in these applications have also been discussed. In the last section, perspectives on the future research directions of MXene-based composites towards the applications of artificial photosynthesis are presented.