Authors
Abstract
He present study investigated the effect of silica coating on catalytic activity of copper-zinc oxide based catalyst for methanol synthesis. Silica coated catalysts prepared using ammonia and L(+)-lysine as promoters of silica coating shows almost same specific surface area and pore size distribution compared with pristine commercial copper-zinc oxide based catalyst, while silica coated catalyst prepared using L(+)-arginine shows significantly lower specific surface area than the pristine catalyst and its mesopores and macropores disappear. Silica coated using ammonia and L(+)-lysine weakly bonds to the commercial catalyst without loading into pores of the catalyst, while silica using L(+)-arginine strongly bonds to the catalyst with loading into the pores of the catalyst. Reduction temperature of fine copper species of the silica coated catalysts shifts to the higher temperature than that of the pristine catalyst, and shift temperatures of the silica coated samples prepared using ammonia and L(+)-lysine are lower than that of the sample prepared using L(+)-arginine, indicating that strongly bonding silica prevents reduction of fine copper species in the commercial catalyst. Among the silica coated catalysts, the coated catalyst prepared with ammonia shows highest COx conversion, and the catalytic activity increase with the decrease of weight ratios of silica to catalyst.
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