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An alternative reduction route of Pd-promoted Co 3 O 4 supported on SBA-15 under ethanol dehydrogenation and decomposition (ED) was studied by an operando time-resolved X-ray absorption spectroscopy (TR-XAS) to understand 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 Co 3 O 4 after calcination and to metallic form after reduction. The reducibility of Co 3 O 4 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 H 2 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 CO 2 was 97.8%, slightly higher than conventional H 2 -reduced 1Pd-10Co/SBA-15. [Display omitted] • Reduction of Co 3 O 4 in ethanol dehydrogenation and decomposition (ED) was disclosed. • Effect of Pd loading on the reducibility of Co 3 O 4 to metallic Co in ED was studied. • Pd with 1.0 wt% provided the highest reducibility of Co 3 O 4 and H 2 yield under ED. • Pd-Co/SBA-15 reduced under ED was active in reverse water gas shift (RWGS). • Pd-Co/SBA-15 reduced under ED provided 97.8% CO selectivity from RWGS. [ABSTRACT FROM AUTHOR]

An influence of support morphology and Pd promoter on physicochemical properties and catalytic performance of Co/SBA-15 in Fischer–Tropsch Synthesis (FTS) was investigated. SBA-15(M) from a hydrothermal synthesis with decane addition had smaller particle size, larger pore size and shorter cavity length which enhanced the dispersion of cobalt oxides, eased diffusion of reactants and improved the FTS performance. 10Co/SBA-15(M) provided the highest and most steady conversions of CO and H 2 with the highest yield of C 5 –C 9 products. The addition of Pd enhanced the reduction of cobalt oxides but produced more methane and light paraffins. [ABSTRACT FROM AUTHOR]

Abstract: The objectives of this work were to compare physicochemical properties of silica-supported cobalt catalysts (with 10wt% Co) prepared by impregnation (10Co-IP) and precipitation using a reverse micelle technique (10Co-RM) and to investigate influence of palladium as a promoter (0.2wt% and 1.0wt%) on properties of 10Co-IP and 10Co-RM. The catalysts were characterized by XRD, H2-TPR, DR-UV–vis, XANES, EXAFS and the reactivity during Fischer–Tropsch synthesis (FTS) was tested at 230°C, 5 bar with H2/CO=2. The particle size of Co3O4 in 10Co-IP was larger than that of 10Co-RM which could contribute to lower selectivity to methane and C2–C4 paraffin products. The addition of 0.2wt% Pd to 10Co-IP and 10Co-RM enhanced the cobalt reducibility, FTS activity and paraffin selectivity. On the other hand, the addition of 1.0wt% Pd resulted in increased methane formation and lower CO conversion. The most suitable catalyst from this work was 0.2Pd-10Co-IP that gave high CO conversion (34.8%) and high mole fraction of paraffins (0.38) in the gasoline range (C5–C9). [Copyright &y& Elsevier]