AuCl3/C catalysts were prepared using activated carbon pretreated at different temperatures. The set of catalysts was evaluated for acetylene hydrochlorination, and the most stable catalyst exhibited the weakest acetylene adsorption capacity, as characterized by the method of temperature-programmed desorption (TPD). The catalysts were also investigated using X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and other methods. It is shown that the activated carbon works as a constituent part of the active site that is responsible for the activation of acetylene. The result provides evidence for the assumption that the Au3+ at the AuCl3/C interface of the catalyst is the active site of the classical AuCl3/C catalyst. (C) 2015 Elsevier Inc. All rights reserved.