Green reduction route via ethanol dehydrogenation and decomposition for Pd-promoted Co3O4/SBA-15 catalysts in reverse water gas shift reaction: An operando time-resolved X-ray absorption spectroscopy investigation

An alternative reduction route of Pd-promoted Co3O4 supported on SBA-15 under ethanol dehydrogenation and decomposition (ED) was studied by an operando time-resolved X-ray absorption spectroscopy (TR-XAS) to un-derstand the insight nature of materials. The catalysts, xPd-10Co/SBA-15, were prepared by co-impregnation method where the Pd content, x = 0.2, 0.5 or 1.0 wt% and Co content = 10.0 wt%. The precursors were transformed to PdO and Co3O4 after calcination and to metallic form after reduction. The reducibility of Co3O4 to metallic Co in 1Pd-10Co/SBA-15 was 98.0%, whereas the metallic form was not produced in the absence of Pd. This catalyst also provided the highest H2 yield of 80% from ED at 500 ???C. The ED-reduced 1Pd-10Co/SBA-15 was tested in reverse water gas shift reaction (RWGS) and characterized by the operando TR-XAS. The CO selectivity from CO2 was 97.8%, slightly higher than conventional H2-reduced 1Pd-10Co/SBA-15.