Multi-interface synergistic photocatalytic 2D/0D/2D TiO₂/Pd/Ti₃C₂ heterojunctions for boosting hydrogen production

Constructing a multi-interface synergistic catalytic system represents an effective strategy for developing highly efficient photocatalysts; however, the challenge lies in fabricating ideal heterojunctions that can fully harness the multiple synergistic effects of the components. In this study, a series of TiO₂/Pd/Ti₃C₂ nanocomposite photocatalysts with 2D/0D/2D heterojunctions were successfully fabricated through a combination of photoreduction and electrostatic self-assembly techniques by varying the mass ratios. Under irradiation from a 300 W xenon lamp, the as-constructed TiO₂/3% Pd/1% Ti₃C₂ heterojunction photocatalyst exhibited a significantly enhanced H₂ evolution rate of 21.60 mmol h^-1 g^-1, which was approximately 135-fold and 25.4-fold higher than those of pristine TiO₂ nanosheets (NSs) and TiO₂/1% Ti₃C₂, respectively. Electrochemical impedance spectroscopy, photoluminescence spectroscopy, and electron spin resonance analysis collectively revealed that the enhanced photocatalytic performance can be attributed to the formation of a synergistic catalytic interface among the TiO₂ NSs, highly active Pd NPs, and monolayer Ti₃C₂ nanosheets. This interface facilitated efficient charge separation, shortened the charge transfer pathways, and enhanced the generation of reactive oxygen species. This study presents a promising strategy for improving catalytic performance through multi-interface synergy and offers a preliminary investigation into the underlying synergistic mechanisms using multiple characterization techniques.