Efficient Photocatalytic CH4 Conversion to C1 Oxygenates on Pd/C-TiO2/g-C3N4 Photocatalyst

In this work, a Pdx/C-TiO2/g-C3N4-y photocatalyst was synthesized by combining g-C3N4 with Ti3C2 through heat treatment, followed by loading with noble metal Pd. Morphological characterization and XPS before and after reaction revealed the formation of a C-TiO2/g-C3N4 Z-scheme heterojunction system with Pd deposited on top. The optimal catalyst, Pd0.8/C-TiO2/g-C3N4-5, exhibited significantly enhanced total C1 yields under mild conditions, achieving 6.1 and 2.6 times the yields of g-C3N4 and C-TiO2, respectively. Notably, the HCHO yield was improved to 3854.79 μmol·g–1·h–1. Mechanistic studies indicated that the C-TiO2/g-C3N4 heterojunction significantly enhanced the CH4 conversion performance by effectively suppressing photogenerated charge recombination. Additionally, the loaded Pd promoted CH4 adsorption and activity, further improving the CH4 conversion efficiency. Furthermore, Pd contributed to the high C1 yield by accelerating the generation of both and •OH radicals.