Yanpeng Pei

Effect of Al2O3 Promoter on a Performance of C1–C14 α-Alcohols Direct Synthesis over Co/AC Catalysts via Fischer–Tropsch Synthesis

The influence of Al2O3 promoter on a performance of C1–C14 α-alcohols direct synthesis from syngas over activated carbon (AC) supported cobalt catalysts (Co/AC catalysts) was investigated using CO hydrogenation evaluation, XRD, HRTEM, H2-TPR, pulsed CO chemisorption, H2-TPD and N2 physisorption techniques. The results obtained showed that the addition of Al2O3 increased significantly the Co component dispersion without remarkably decreasing its reducibility and inhibited its aggregation during reaction, resulting in greatly enhanced reaction activity as well as increased selectivity towards liquid products. Appropriate amounts of Al2O3 can promote the formation of Co2C, leading to an increase of total alcohol fraction in the liquid products. Moreover, the Al2O3 addition can further promote the formation of higher alcohols (C6–C14 alcohols).Graphical Abstract

Synthesis of Mixed Alcohols from CO Hydrogenation over Iron and Nickel Metal Phosphide Catalysts

A series of silica supported iron and nickel metal phosphides with different molar ratios of P to metal were synthesized by the temperature programmed reduction method. Their catalytic performance for CO hydrogenation in a fixed bed reactor was tested with the conditions of 553 K, 5.0 MPa, and H2:CO = 2 (molar ratio). With the FePx/SiO2 catalysts (x denotes the molar ratio of P to metal), the product was a mixture of oxygenates containing methanol as the major component. With the NiPx/SiO2 samples, the liquid product was mainly methanol. The Fe2P, Fe3P, Ni, Ni2P, Ni3P, and Ni12P5 phases were stable during CO hydrogenation, while most of the metallic Fe phase transformed into iron carbide.

Study on the effect of alkali promoters on the formation of cobalt carbide (Co2C) and on the performance of Co2C via CO hydrogenation reaction

The present investigation deals with an alkali metal assisted synthesis of cobalt carbide (Co2C), starting from carburizing reduced complex precursors (obtained from Co3O4 with the addition of Li2O, Na2O and K2O) using CO as a carburization source. It is found that the Co2C formation could be significantly accelerated by the Li component. A comparative study reveals that the promotion effect of Li component may be related to the H2 adsorption on the reduced precursor, which enhanced the ability of the precursor to react with CO. Furthermore, the Co2C prepared from the precursor containing Li component shows a considerable increase in activity for CO hydrogenation and an improved fraction of higher alcohols in the total alcohol products, compared to the Co2C prepared without promoters. An attempt is made to elucidate the catalytic behavior of the as-prepared Co2C samples.

Fischer-Tropsch synthesis: Characterizing and reaction testing of Co2C/SiO2 and Co2C/Al2O3 catalysts

SiO2- and Al2O3-supported CO2C catalysts were prepared by carburizing supported Co precursors with CO. The catalysts were characterized by N-2 physisorption, X-ray diffraction and H-2 temperature-programmed reduction techniques, and evaluated by the Fischer-Tropsch (F-T) reaction. The results showed that SiO2- and Al2O3-supported Co2C catalysts could be successfully obtained but sufficient carburization time was required. All of the as-prepared supported Co2C catalysts exhibited activity and selectivity towards alcohols. It is considered that surface metallic Co species contributed to the activity, surface Co2C species were responsible for the formation of alcohols, and bulk CO2C species were inert during the F-T reaction