Yttrium chloride-modified Au/AC catalysts for acetylene hydrochlorination with improved activity and stability

The addition of yttrium chloride(YCl) to an activated carbon-supported Au catalyst(Au/AC) can markedly promote the catalytic performance of acetylene hydrochlorination to the vinyl chloride monomer(VCM), The structure and physicochemical features of the YCl-modified catalysts(Y-Au/AC)were measured by X-ray diffraction, X-ray photoelectron spectroscopy, temperature-programmed reduction, CH-temperature programmed desorption, and scanning transmission electron microscopy.The presence of YClwas found suppressing the reduction of highly oxidized Au(δ=1,3) to metallic Au~0 dependently and thus retard the agglomeration of Au nanoparticles during the reaction. In addition,the additive of YClto the Au/AC catalyst greatly inhibits the coke deposition on the catalyst surface. The optimized catalyst with an atomic ratio of Y/Au = 5(1 wt% Au loading weight) yields an 87.8% acetylene conversion and almost 100% selectivity for VCM under the reaction of GHSV(CH) = 800 hat 180 ℃.The durability test indicates that the 5 Y-1 Au/AC catalyst maintains high catalytic activity for more than2300 h at 30 hGHSV(CH) and 180 ℃, indicating great promise as a non-mercury catalyst for PVC manufacture.

The addition of yttrium chloride(YCl_3) to an activated carbon-supported Au catalyst(Au/AC) can markedly promote the catalytic performance of acetylene hydrochlorination to the vinyl chloride monomer(VCM), The structure and physicochemical features of the YCl_3-modified catalysts(Y-Au/AC)were measured by X-ray diffraction, X-ray photoelectron spectroscopy, temperature-programmed reduction, C_2 H_2-temperature programmed desorption, and scanning transmission electron microscopy.The presence of YCl_3 was found suppressing the reduction of highly oxidized Au^(δ+)(δ=1,3) to metallic Au^0 dependently and thus retard the agglomeration of Au nanoparticles during the reaction. In addition,the additive of YCl_3 to the Au/AC catalyst greatly inhibits the coke deposition on the catalyst surface. The optimized catalyst with an atomic ratio of Y/Au = 5(1 wt% Au loading weight) yields an 87.8% acetylene conversion and almost 100% selectivity for VCM under the reaction of GHSV(C_2 H_2) = 800 h^(-1) at 180 ℃.The durability test indicates that the 5 Y-1 Au/AC catalyst maintains high catalytic activity for more than2300 h at 30 h^(-1) GHSV(C_2 H_2) and 180 ℃, indicating great promise as a non-mercury catalyst for PVC manufacture.