Yongwu Lu

High Selectivity Higher Alcohols Synthesis from Syngas over Three‐Dimensionally Ordered Macroporous Cu‐Fe Catalysts

We show that higher alcohols can be produced with high selectivity from syngas over three‐dimensionally ordered macroporous Cu–Fe catalyst. The catalyst was developed by using a glyoxylate route colloidal crystal template method. The high intrinsic activity was ascribed to three factors. First, the unique ordered structure has a large pore size and interconnected macroporous tunnels of the catalyst with a large accessible surface area improves the catalytic activity. Second, a high density of uniformly distributed defective Cu0 and χ‐Fe5C2 nanoparticles derived from the glyoxylate route helps to provide abundant, active, stable dual sites. Third, atomic steps on the Cu surface, induced by planar defects and lattice strain, serve as high‐activity oxygenation sites; and active χ‐Fe5C2 chain‐growth sites surrounds the defective and strained form of Cu surface intimately, which results in a synergetic effect between the active and stable Cu–FexCy dual sites for higher alcohols synthesis.

Fischer–Tropsch synthesis of liquid hydrocarbons over mesoporous SBA-15 supported cobalt catalysts

The influence of cobalt loading (10–30 wt% Co) and pore size of SBA-15 support on the physico-chemical and catalytic performance of mesoporous Co/SBA-15 catalysts for the Fischer–Tropsch synthesis (FTS) reaction (T = 245 °C, P = 290 psig, H2/CO = 2, and GHSV = 2000 h−1) has been investigated. Catalysts were characterized by N2 adsorption–desorption, X-ray diffraction (XRD), electron microscopy, and temperature-programmed reduction (TPR). The dispersion of Co/SBA-15 decreased and the extent of cobalt reduction increased with increasing either the cobalt loading or pore size of SBA-15. A maximum CO conversion was found for the sample with 20 wt% Co loading. More methane and less C5+ hydrocarbons were produced over less reducible 10 wt% Co loaded sample. The 20Co/SBA-15 catalysts with larger pores led to larger cobalt crystallite size, lower dispersion and higher reducibility. CO conversion increased with the increase of pore size in the range studied. The 20Co/SBA-15 catalysts with larger cobalt crystallite size showed higher C5+ selectivity for the FTS. Finally, at comparable Co loading, CO conversion of Co/SBA-15 catalysts were to be about 2 times greater than a Co/SiO2 sample, with only a minor difference in product selectivity.

Synthesis of tungsten carbide nanoparticles in biochar matrix as a catalyst for dry reforming of methane to syngas

Tungsten carbide (WC) nanoparticles were synthesized by carbothermal reduction (CR) of tungsten-promoted biochar. The tungsten carbide nanoparticles were characterized for physicochemical properties by multiple morphological and structural methods (e.g. SEM, TEM, and XRD). Characterization results revealed that the transformation of tungsten oxide (WO3) to tungsten carbide nanoparticles involved the following sequence steps: WO3 → WO2 → W → W2C → WC. The lower the reaction temperature, the lower the CH4 and CO2 conversions, as well as the lower CO yield, since dry reforming is an endothermic reaction. CH4 conversion was observed to decrease with an increase in CH4/CO2 ratio, whereas CO2 conversion increased with an increase in CH4/CO2 ratio. The higher the GHSV, the lower the CH4 and CO2 conversions as well as the lower the CO yield. Stability testing of the tungsten carbide nanoparticles in the biochar matrix showed no catalyst deactivation during the 500 hours test duration.

Catalytic Conversion of Biomass-derived Syngas to Gasoline Range Hydrocarbons

Catalytic conversion of biomass-derived syngas (bio-syngas) into gasoline range hydrocarbons has been regarded as one of potential routes to utilize biomass. In this route, biomass is firstly converted into bio-syngas through biomass gasification. Then bio-syngas is catalytically converted into transportation fuels or chemicals. In this paper, catalytic synthesis of gasoline range hydrocarbons by using model syngas similar to bio-syngas has been carried out over Mo/HZSM-5 catalysts. Different system temperatures were adopted in the experiments to figure out the effects of reaction parameters. The products were analyzed by GC and GC-MS. The catalysts were characterized by SEM-EDS and TEM. The results showed that Mo/HZSM-5 was active in model bio-syngas.