Synergistic enhancement of solar-driven hydrogen evolution via Ni-doped TiO2–MXene hybrid photocatalyst

Developing high-efficiency photocatalysts for sustainable hydrogen production is a key priority in solar energy conversion. Here, we present a TiO₂-based photocatalyst co-modified with nickel dopants and Ti₃C₂T_x MXene to improve light absorption, charge separation, and interfacial charge transport. The hybrid material was synthesized via HF etching of Ti₃AlC₂ MAX phase followed by nickel doping and thermal calcination. Physicochemical characterization (XRD, SEM/TEM, XPS, UV–Vis, PL, FTIR, Raman) confirmed successful integration of TiO₂, Ni²⁺ species, and partially oxidized MXene sheets. Electrochemical impedance spectroscopy (EIS) and transient photocurrent response measurements revealed improved charge mobility and reduced recombination. Among the samples tested, the TiO₂–2 % Ni–10 % MXene composite showed the best performance, achieving a hydrogen evolution rate of 47.2 mmol h⁻¹ g⁻¹ and an apparent quantum yield of 5.5 % under UV light. This enhanced activity results from the synergistic effects of Ni doping (introducing shallow traps and promoting proton reduction) and the conductive MXene phase (facilitating charge transfer and providing active sites). The study offers a scalable dual-modification strategy for designing efficient TiO₂-based photocatalysts and contributes valuable insights into the rational development of advanced materials for solar-driven hydrogen generation.