Highly efficient photocatalytic non-oxidative coupling of methane over a novel Ag-modified TiO2–SiO2 catalyst

• Ag/TiO 2 –SiO 2 was developed for photocatalytic non-oxidative methane coupling. • 0.5%Ag/TS showed the highest C 2 H 6 formation rate of about 450 μmol g −1 h −1 . • C 2 H 6 was the main coupling product under simulated sunlight irradiation. • The catalyst maintained stable performance during repeated reaction cycles. • Trapping tests indicated that photogenerated holes play a major role in methane activation. Photocatalytic non-oxidative coupling of methane (NOCM) is a promising approach for converting CH 4 into higher-value hydrocarbons under mild conditions without the use of external oxidants. In this work, a silver-modified TiO 2 –SiO 2 (Ag/TS) photocatalyst was prepared by a facile photodeposition method and evaluated for photocatalytic methane coupling under simulated sunlight irradiation. Structural characterization confirmed that the anatase TiO 2 –SiO 2 framework and mesoporous structure were preserved after Ag loading, while XPS analysis revealed the coexistence of Ag 0 and Ag + species on the catalyst surface. UV–Vis diffuse reflectance spectroscopy showed enhanced light absorption after Ag modification, whereas PL and EIS analyses suggested improved charge separation and suppressed recombination of photogenerated charge carriers. Among the prepared samples, 0.5%Ag/TS exhibited the highest C 2 H 6 formation rate of approximately 450 µmol g −1 h −1 under the present reaction conditions. C 2 H 6 was the major coupling product, while only small amounts of CO 2 and trace C 2+ hydrocarbons were detected. The catalyst also showed good stability over repeated cycles. In addition, trapping experiments using KI and IPA suggested that photogenerated holes play an important role in methane activation, while OH-related species may also participate to a lesser extent. These results indicate that Ag modification effectively improves the photocatalytic performance of TiO 2 –SiO 2 for methane coupling under mild conditions.