Efficient And Selective Interplay Revealed: Co2 Reduction To Co Over Zro2 By Light With Further Reduction To Methane Over Ni-0 By Heat Converted From Light

The reaction mechanism of CO2 photoreduction into methane was elucidated by time-course monitoring of the mass chromatogram, in situ FTIR spectroscopy, and in situ extended X-ray absorption fine structure (EXAFS). Under (CO2)-C-13, H-2, and UV/Vis light, (CH4)-C-13 was formed at a rate of 0.98 mmol h(-1) g(cat)(-1) using Ni (10 wt %)-ZrO2 that was effective at 96 kPa. Under UV/Vis light irradiation, the (CO2)-C-13 exchange reaction and FTIR identified physisorbed/chemisorbed bicarbonate and the reduction because of charge separation in/on ZrO2, followed by the transfer of formate and CO onto the Ni surface. EXAFS confirmed exclusive presence of Ni-0 sites. Then, FTIR spectroscopy detected methyl species on Ni-0, which was reversibly heated to 394 K owing to the heat converted from light. With D2O and H-2, the H/D ratio in the formed methane agreed with reactant H/D ratio. This study paves the way for using first row transition metals for solar fuel generation using only UV/Vis light.