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The effect of various reduced catalysts for the upgrading of bio-oil produced by fast pyrolysis in a small batch reactor was evaluated using reduced Ni/SiO 2 , Co/SiO 2 , Pt/SiO 2 , Pd/SiO 2 , and conventional sulfided CoMo/Al 2 O 3 catalysts. All of the reduced catalysts were prepared by incipient wetness impregnation. Hydrodeoxygenation (HDO) reactions carried out in the H 2 pressure range of 1-5 MPa and temperature range of 300-350 °C using guaiacol and woody tar as model compounds for fast pyrolysis oil demonstrated that at 300 °C, higher guaiacol conversion was achieved with the reduced Co/SiO 2 , Ni/SiO 2 , and Pd/SiO 2 catalysts compared with the conventional sulfide CoMo/Al 2 O 3 catalyst. However, only the reduced Co/SiO 2 catalyst exhibited high HDO activity and selectivity towards aromatics in the guaiacol HDO reaction. The reduced Co/SiO 2 catalyst also exhibited high HDO activity and selectivity towards aromatics in the HDO of woody tar, indicating that this catalyst may be active for direct deoxygenation of phenol yielding mostly benzene. Thus, the reduced catalysts, especially the Co/SiO 2 catalyst, can be considered to be potential candidates for use as HDO catalysts with improved activity and selectivity.

One-pot synthesized Ti-SBA-15 mesoporous materials with various Ti loadings of 0.808-6.78 mol% were applied as heterogeneous solid acid catalysts for simultaneous esterification and transesterification of vegetable oils with methanol into high-quality biodiesel fuel (BDF) at 200 o C under autogeneous pressure. According to the diffuse-reflectance (DR) UV-Vis spectra, diffuse-reflectance infrared Fourier transform (DRIFT) spectra and pulsed ammonia (NH 3 ) chemisorption studies combined with other conventional characterizations, the catalytically active site for high-quality BDF synthesis was mostly related to the tetrahedral Ti 4+ species with weak Lewis acid character, which differential heat of NH 3 adsorption was lower than 90 kJ mmol -1 . Due to that the tetrahedral Ti 4+ species were accessible on largely mesoporous framework, the Ti-SBA-15 catalyst gave much higher activity in transesterification of crude Jatropha oil (CJO) with methanol than microporous titanosilicate of TS-1 and commercial TiO 2 nanocrystallites. Among them, the 3Ti-SBA-15 catalyst with a Ti loading of 2.46 mol% showed a highest fatty acid methyl ester (FAME) content of 90 mass% at 200 o C for 3 h using a methanol-to-oil molar ratio of 27. When the reaction period and methanol-to-oil molar ratio were increased to 3-6 h and 108, respectively, a great variety of edible and non-edible vegetable oils with various acid values (0.06-190 3 mg KOH g -l ), including refined soybean oil (RSO), refined rapeseed oil (RRO), waste cooking oil (WCO), crude palm oil (CPO), CJO and palm fatty acid distillates (PFAD), was directly transformed into high-quality BDFs, which met with a European standard (EN 14214:2009), over 3Ti-SBA-15 catalyst at 200 o C. The used 3Ti-SBA-15 catalyst was easily regenerated by calcination and its high activity was maintained. Most importantly, the 3Ti-SBA-15 catalysts could resist 5 wt% of water or 30 wt% of free fatty acid (FFA), which tolerance levels were several ten times better than those of homogeneous and heterogeneous catalysts in the current BDF production technology.

Co/SiO 2 catalysts were prepared by the incipient wetness method using the aqueous Co nitrate solution modified with various organic acids and/or chelating agents followed by drying and calcination. After H 2 reduction at 773 K, the catalyst prepared with nitrilotriacetic acid (NTA) showed Fischer-Tropsch synthesis (FTS) activity ca. 3 times higher than the catalyst without additives under mild reaction conditions (503 K, 1.1 MPa).

Direct conversion of dilute CO2 contained in power plant or industrial exhaust gas and the atmosphere into high-concentration hydrocarbons without a need of separate CO2 capture and purification processes is one of the awaited technologies in envisioned low-carbon societies. In this study, we investigated the performance of integrated CO2 capture and reduction to CH4 over Nibased dual functional catalysts promoted with Na, K and Ca. Ni/Na-γ-Al2O3 exhibited the highest activity for integrated CO2 (5% CO2) capture and reduction, achieving high CO2 conversion (>96%) and CH4 selectivity (>93%). In addition, very low concentration CO2 (100 ppm CO2) was successfully converted to 11.5% CH4 at the peak point (>1000 times higher concentration than that of the supplied CO2) over Ni/Na-γ-Al2O3. The Ni-based dual functional catalyst exhibited a high CO2 conversion exceeding 90%, even when 20%O2 was present during CO2 capture. Furthermore, an increased operation pressure had positive impacts on both CO2 capture and CH4 formation, and these advantageous effects were also observed when CO2 concentration was at the level of atmospheric CO2 (100-400 ppm). As pressure increased from 0.1 to 0.9 MPa, CH4 production capacity with 400 ppm CO2 was enhanced from 111 to 160 µmol gcat -1 . The approach in combination with the efficient catalyst shows encouraging promises for CO2 utilization, enabling direct air capture-conversion to value-added chemicals.CH4 productivity increased from 188 to 266 μmol gcat −1 . In addition, the effect of pressure on catalyst performance was also investigated at very low CO2 levels of 100 and 400 ppm, and high pressure was found to positively affect both CO2 capture and CH4 formation. These results suggest that high pressure enhances the CO2 absorption and CH4 formation capacities of dual-functional catalysts and allows for efficient integrated CO2 capture and reduction into CH4 even at atmospheric levels of CO2. The approach, in combination with the efficient catalyst, is promising for CO2 utilization, thus enabling direct air capture-conversion to value-added chemicals.

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