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Alternative solvent to aqua regia to activate Au/AC catalysts for the hydrochlorination of acetylene.
- Source :
-
Journal of Catalysis . Jun2017, Vol. 350, p149-158. 10p. - Publication Year :
- 2017
-
Abstract
- In this paper, we demonstrate that the less toxic, relatively safe, and recyclable organic aqua regia (OAR) can be employed as a greener alternative solvent to conventional aqua regia to activate Au/AC catalysts for the hydrochlorination of acetylene. We show that Au-based catalysts prepared with HAuCl 4 as precursor can be prepared initially in water (Au(H 2 O)/AC). Although catalysts prepared from aqueous HAuCl 4 showed poor activity, it can be significantly enhanced by catalyst activation in OAR (Au(H 2 O)/AC(OAR)). In contrast to the catalyst activation procedure using aqua regia (Au(aq)/AC), we demonstrate that the new activation procedure leads to both improved activity and stability of the resulting Au(H 2 O)/AC(OAR) catalyst. Further analyses of X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) show that the variations of Au particle size and chemical state caused by OAR treatment promote Au oxidation and high dispersion. In addition, temperature-programmed reduction (TPR) and temperature-programmed desorption (TPD) indicated that the presence of residual sulfur and nitrogen species may help stabilize the cationic Au 3+ species and generate a catalyst less prone to deactivation by increasing the reduction temperature of the Au 3+ species and enhancing the adsorption of hydrogen chloride over the Au(H 2 O)/AC(OAR) catalyst. These results suggest that OAR can be substituted for conventional solvents to activate Au/AC catalysts for the hydrochlorination of acetylene. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00219517
- Volume :
- 350
- Database :
- Academic Search Index
- Journal :
- Journal of Catalysis
- Publication Type :
- Academic Journal
- Accession number :
- 122911971
- Full Text :
- https://doi.org/10.1016/j.jcat.2017.02.027