Fig. 1: Photocatalytic OCM activity over PdCu nanoalloy decorated TiO2.
a C2 yield rate over different noble co-catalysts decorated TiO2 with the equal molar amount to Pd. b Influence of second transition metal cocatalysts with the equal molar amount to Pd on C2 production at 1.5-hour run. c CH4 total conversion rate and C2 selectivity over PdCu/TiO2 with different CH4: O2 ratios (the ratios were 53: 1, 114: 1, 176: 1, and 373: 1, respectively). Error bars (standard deviation) in the figure were obtained from three sampling runs. d C2 synthesis over PdCu/TiO2 during an intermittent 112-hour reaction with the CH4: O2 ratio of 373: 1, these data were collected every 30 min. e Summary of turnover frequency (TOF) and turnover number (TON) achieved on PdCu/TiO2 and other reported representative photocatalysts (λ > 300 nm) at room temperature (1: AuPd/ZnO79; 2: Au/ZnO80; 3: Ga2O3-K81; 4: MgO-SiO282; 5: Ce-Al2O383; 6: Au/WO323; 7: Ag-H3PW12O40/TiO233; 8: Pt-CuOx/TiO212; 9: Pt/Ga-TiO2-SiO284; 10: Au/TiO214; 11: TiO2/SiO285; 12: SiO2-Al2O3-TiO286; 13: H-MOR87; 14: FSM-1688; 15: GaN: ZnO89; 16: Zn5(OH)8Cl2·H2O90, 17: this work.). The insert figure is the zoomed rectangle region indicated with the dash line in the main panel, showing the range of TON between 0–10 and TOF between 0–0.9. Among them, the values of photocatalyst 3, 4, 13 and 14 are still too small to see even in the enlarged insert. The calculation method is shown in the Method section. Reaction condition in (a, b): gas hourly space velocity (GHSV = 342,000 mL gcat−1 hour−1), CH4: O2 = 114: 1, 10% of CH4, Ar as balance gas, 365 nm LED 40 W, 30 °C; the reaction condition in (c) was similar to the above except the ratio of CH4: O2 and the reaction condition in (d) was also similar except the ratio of CH4: O2 was changed to 373: 1. Source data are provided as a Source Data file.
