MXenes as electron mediators in photocatalysis: Structural advantages and integration into advanced heterojunctions

In this work, we investigate MXene-based heterojunctions engineered to improve photocatalytic performance by promoting interfacial charge transfer and suppressing electron–hole recombination. The coupling of Ti 3 C 2 MXene with ZnO is explored as a strategy to obtain more favourable band alignment. Multiple synthesis routes are employed, followed by comprehensive structural, morphological, and electronic characterization. Complementary Density Functional Theory (DFT) calculations are proposed to elucidate reaction barriers for water oxidation and hydrogen adsorption, providing theoretical insight into the observed catalytic behaviour. Overall, this study aims to advance the development of MXene-based heterojunction photocatalysts for sustainable hydrogen production and broader solar-driven applications. The ternary mixed systems were synthesized using two different methods, highlighting the key role of the preparation route in determining the structural properties and photocatalytic performance of the materials. Results obtained in hydrogen production, even preliminary, are encouraging especially for the ternary system MXene with zinc oxide coupled with cerium oxide. • Heterojunction systems were developed by coupling MXene with ZnO or CeO 2_ ZnO. • The photocatalysts were prepared using hydrothermal or precipitation methods. • The materials were characterized by morphological, optical, and structural analysis. • DFT calculations were performed to propose a reaction mechanism. • The MXene_CeO 2 _ZnO sample exhibited the best performance in H 2 production.