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 H-2 production, CO2 reduction to solar fuels, and N-2 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.