Synergistic Interfacial Engineering of Green TiO ₂ @g-C ₃ N ₄ for Noble-Metal-Free Photocatalytic H ₂ Generation under Natural Sunlight

High Resolution Image Download MS PowerPoint Slide The plausible design for accurate, sunlight-responsive photocatalysts for feasible hydrogen generation remains a critical focus in solar energy conversion exploration. In this work, a green TiO 2 @g-C 3 N 4 heterojunction was produced and systematically assessed for enhanced photocatalytic H 2 evolution in an aqueous glycerol solution according to direct sunlight. Structural, morphological, and interfacial features were extensively determined utilizing TEM, XPS, and photoluminescence (PL) spectroscopy, verifying the accomplished generation of a robust heterojunction with strong Ti–N–C interfacial bonding. Gas chromatography confirmed the absence of H 2 and O 2 prior to irradiation, guaranteeing precise baseline assessments. Pristine g-C 3 N 4 and green TiO 2 displayed hydrogen generation rates of 3.75 and 44.5 μmolh –1, respectively, while green TiO 2 most notably surpassed traditional white TiO 2 (<40 μmolh –1 ) owing to oxygen vacancies boosting visible-light absorption. Interestingly, the designed green TiO 2 @g-C 3 N 4 heterostructure attained a superior H 2 evolution rate of 110.25 μmol h –1, a 29.4- and 2.4-fold improvement over g-C 3 N 4 and green TiO 2, respectively. This elevated photocatalytic achievement is credited to escalated interfacial charge movement, prolonged charge carrier lifetimes, and upgraded surface redox kinetics. This work offers beneficial insights into the rational design of g-C 3 N 4 -based heterostructures for highly effective, noble-metal-free, solar-driven hydrogen production.