MXene-derived TiO2 nanoparticles coated with C/N shell for photocatalytic hydrogen generation under solar light

Photocatalytic hydrogen production offers a sustainable and innovative solution to address environmental challenges and global energy shortages by leveraging solar energy. Developing highly efficient photocatalysts is pivotal for advancing photocatalysis technology and facilitating its practical applications. In this study, Ti₃C₂T_X MXene was used as a precursor of TiO₂ nanoparticles coated with a carbon/nitrogen (C/N) shell for photocatalytic hydrogen generation under simulated solar light. The fabrication strategy was based on a straightforward one-step annealing process. The photoactivity of the sample was optimized through the following: (1) tuning the ratio of precursors MXene to gCN calcinated in the air at 550 °C, and (2) controlling the temperature of the annealing process of the sample, which indicated the most outstanding hydrogen evolution yield in strategy 1° (MXene:gCN = 1:19). The optimized sample, C/N@TiO₂, demonstrated an exceptional H₂ production rate of 37.66 mmol/g (37,660 µmol/g), approximately 655 times and 37 times higher than those of gCN (57 µmol/g) and TiO₂ derived from pristine MXene (1024 µmol/g), respectively. This remarkable photocatalytic performance is attributed to the formation of a carbon/nitrogen (C/N) shell, which made TiO₂ extraordinarily robust in the experimental conditions, promoting charge separation, suppressing electron–hole recombination, and enhancing visible light absorption. Additionally, density functional theory (DFT) calculations revealed that the C/N layer serves as an electron-rich active site, further promoting efficient photocatalytic hydrogen generation. This study provides a facile and cost-effective pathway to advancing green hydrogen production technologies. The findings underscore the potential of photocatalytic systems for sustainable energy development, paving the way for scalable renewable energy solutions.