Robust and Recyclable Single-Atom and Cluster-like Cu-Based Catalysts for Methanol Oxidative Carbonylation to Dimethyl Carbonate
Wenjie Li, Shanlin Gao, Chunbo Lai, Xinling Li, Wanjing Xiao, Xinyu Wang, Huibo Lin, Yang Zhang, Haijun Liu, Yang Gan, Chenghua Xu, Luke Higgins, Andrew M. Beale, Marc Pera‐Titus, Zhiyong Deng
Abstract
High Resolution Image Download MS PowerPoint Slide Methanol oxidative carbonylation is a highly desired reaction for the industrial production of dimethyl carbonate (DMC), offering a more sustainable alternative to the conventional, environmentally unfriendly phosgene-methanol process. Although supported copper nanoparticle catalysts can facilitate this reaction, their rapid deactivation due to Cu sintering and overoxidation limits their industrial applicability. In this study, we present robust and reusable single-atoms and cluster-like Cu catalysts (catalyst loading up to 6.5 wt %) supported on N-doped carbon, synthesized via pyrolysis of Cu-doped ZIF-8 precursors. The formation and stability of highly dispersed Cu species during the reaction was confirmed using a comprehensive suite of characterization techniques, including X-ray diffraction (XRD), Fourier transform infrared (FT-IR), high-resolution transmission electron microscopy (HR-TEM), aberration corrected high angle annular dark field-scanning transmission electron microscopy (AC-HAADF-STEM), X-ray photoelectron spectroscopy (XPS), NH 3 -TPD, H 2 -TPR, and X-ray absorption spectroscopy (XAS). This unique copper architecture achieved an exceptional DMC selectivity of 99.4% and a space-time yield of 3249 mg DMC·g –1 ·h –1 (TOF DMC,B = 34.4 h –1; TOF DMC,S = 294 h –1 ) at 120 °C for 2 h. The catalysts demonstrated excellent reusability, maintaining their performance over at least seven consecutive runs without deactivation. Postreaction analysis of the spent catalyst after seven runs revealed that Cu was largely free of leaching, sintering, and overoxidation.