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Au catalysts supported with carbon‐based carriers have been extensively studied for the hydrochlorination of acetylene and expected to replace toxic mercury catalysts. However, removal of the highly corrosive aqua regia used in the preparation of carbon‐based catalysts while maintaining catalytic activity and stability remains a key challenge. Herein, we present a green technology carrier, activated carbon fibers (ACF), to support gold catalysts for the hydrochlorination of acetylene. TPD and XPS analyses confirmed the presence of surface oxygen‐containing functional groups (SOGs) and pyrrolic N species on the ACF. The Au/ACF−H2O catalyst exhibited better catalytic activity and stability than Au/ROX0.8(AQ)−H2O. Characterization results revealed that the catalytic properties of Au/ACF−H2O could be attributed to the anchoring and stabilization of gold active species on the SOGs, leading to atomic dispersion, and to the improvement of HCl adsorption with the synergistic effect of electron‐donating pyrrolic N groups. The results indicated that usage of this green carrier can be considered as the a new approach to reduce or eliminate the use of strong oxidizing reagents in the preparation of Au catalysts. [ABSTRACT FROM AUTHOR]

Gold catalysts have been reported to exhibit good performance in aerobic oxidation of alcohols, but the intrinsic origin of the catalytic reactivity is still illusive. The catalyst preparation method, the morphology of the gold particles, and even the support might be key factors that determine the activity. Here, we prepared a series of gold catalysts with different supports, i.e., the hydrotalcite (HT), ZnO, MgO, Al2O3, and SiO2, by using the atomically controlled Au25 nanoclusters (NCs) as the gold precursor. The characterization results of the X-ray diffraction (XRD), UV-vis and transmission electron microscopy (TEM) show that the gold particles were mostly uniformly distributed on the supports, with a mean particle size within 3 nm. In aerobic oxidation of benzyl alcohol, the MgAl-HT- and Al2O3-supported Au25 NCs display good performances, with turnover frequency (TOF) values of ~2927 and 2892 h−1, respectively, whereas the SiO2-, MgO-, and ZnO-supported analogues show much inferior activity. The high resolution TEM and X-ray photoelectron spectra (XPS) results suggest that the interactions between gold and the supports in different samples are differing, which influences the morphology and the nature of gold. Our results further point to the importance of acid-base property of the support and the metal-support synergy rather than the gold particle size alone in achieving high-performance in selective alcohol oxidation. Moreover, this work provided a good way to design gold catalysts with controllable sizes that is crucial for understanding the reaction process in aerobic oxidation of alcohol. [ABSTRACT FROM AUTHOR]

There is great potential for carbon-supported gold catalysts to replace toxic mercuric chloride-based catalysts in the acetylene hydrochlorination, which is a key process for producing PVC. However, the catalyst design is essentially hindered by the difficulties in enhancing the catalytic activity of cationic gold and suppressing the deactivation of active species. We report a strategy for self-oxidation of Au3+ by the Au-SILP system with the [Bmim][Cl 3 ] ILs. This strategy can stabilize all gold species in the state of highly oxidized Au3+ instead of coexisting in the Au3+/Au+ site, which makes the catalyst exhibit excellent catalytic activity. High coordination numbers Au-Cl entities reduce the electron transfer between Au3+ and C 2 H 2 and weaken the adsorption of C 2 H 2 on the Au active sites. Furthermore, [Bmim][Cl 3 ] ILs can self-oxidize gold nanoparticles on the support surface into Au3+. This study provides a new method for improving the stability and activity of gold-based acetylene hydrochlorination catalysts. [Display omitted] • The self-oxidation of Au3+ catalyst are successfully synthesized. • Self-oxidation of high-valence gold via sacrificial [Bmim][Cl 3 ] high activity and long lifetime catalyst design of Au-SILP catalysts. • High coordination numbers Au-Cl entities reduce the electron transfer between Au3+ and C 2 H 2 and weaken the adsorption of C 2 H 2 on the Au active sites. [ABSTRACT FROM AUTHOR]