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

The addition of yttrium chloride (YCl3) 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 YCl3-modified catalysts (Y-Au/AC) were measured by X-ray diffraction, X-ray photoelectron spectroscopy, temperature-programmed reduction, C2H2-temperature programmed desorption, and scanning transmission electron microscopy. The presence of YCl3 was found suppressing the reduction of highly oxidized Auδ+ (δ = 1, 3) to metallic Au0 dependently and thus retard the agglomeration of Au nanoparticles during the reaction. In addition, the additive of YCl3 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(C2H2) = 800 h−1 at 180 °C. The durability test indicates that the 5Y-1Au/AC catalyst maintains high catalytic activity for more than 2300 h at 30 h−1 GHSV(C2H2) and 180 °C, indicating great promise as a non-mercury catalyst for PVC manufacture.