Abstract: To obtain a highly dispersed Co-based catalyst, dielectric-barrier discharge (DBD) plasma instead of calcination was used to decompose the precursors at low temperature. It was found that DBD plasma can not only replace calcination to get catalyst precursor decomposed but also be quicker and more energy-saving. The catalyst samples treated by the two methods had similar surface area, while pore volume and pore size of the sample treated by DBD was larger than that by calcination. Temperature-programmed reduction results showed that the catalyst treated by DBD resulted in higher Co dispersion and stronger interaction between Co and the support than that by calcination. X-ray diffraction results indicated that Co₃O₄ was the main Co species after DBD treatment. The Co₃O₄ crystallite diameter was 11.8 nm, which was smaller than that of calcined counterparts. Transmission electron microscopy results proved that DBD treatment resulted in smaller Co oxide clusters, more homogeneous Co distribution, and less agglomeration. Fischer-Tropsch synthesis performance evaluation results showed that DBD treated catalyst had higher CO conversion and C₅₊ selectivity than the calcined one.

Key words: plasma treatment, Co-based catalyst, dielectric-barrier discharge, precursor decomposition, Fischer-Tropsch synthesis