Cu0/Cuδ+ site construction and its catalytic role in acetylene hydrochlorination

Abstract

In view of the dearth of active components and the unsatisfactory dispersion of Cu-based catalysts, it is imperative to undertake a detailed investigation of catalysts with enhanced catalytic performance. In order to achieve a balance between the catalytic activity and stability in the reaction process, a series of P-atom doped Cu⁰/Cu^δ+ binary Cu-based catalysts were prepared by means of heteroatom introduction and heat treatment. The introduction of P enhanced the stability of Cu during heat treatment, thereby inhibiting the excessive agglomeration of Cu. The structure of the Cu⁰/Cu^δ+ binary catalyst was modified through heat treatment and HCl activation, and the relationship between its structure and catalytic activity was subsequently investigated. The activation process of HCl facilitated the conversion of the Cu⁰ state to the Cu-Cl state and augmented the valence state of Cu. The valence modulation of the Cu site by HCl during the reaction prevented the over-reduction of the Cu site by acetylene and enhanced the stability of the catalyst. The 3Cu/5CuP/AC-800 catalyst was operated for 50 h without significant deactivation under the reaction conditions of T = 180 °C, V(HCl)/V(C₂H₂) = 1.15 and GHSV(C₂H₂) = 180 h^-1. This design strategy provides a novel reference point for further studies of CuCl₂ based catalysts for acetylene hydrochlorination.