Mechanochemical synthesis of a high-surface-area Pd/α-Al2O3 catalyst for CO oxidative coupling to dimethyl oxalate reaction

Abstract

Mechanochemistry has emerged as a highly promising approach in the field of synthesizing catalytic materials. In this work, high-surface-area α-Al₂O₃ with abundant hydroxyls was synthesized by a mechanochemical method. The Pd/α-Al₂O₃ catalyst possessed high catalytic activity and excellent stability in CO oxidative coupling to dimethyl oxalate (DMO) reaction. Moreover, we provide a strategy to tune the interaction of Pd and α-Al₂O₃ support by modulating the number of hydroxyls of α-Al₂O₃. Detailed characterizations indicated that the surface hydroxyls of α-Al₂O₃ supports play an important role in inhibiting Pd nanoparticles aggregation and enhancing the interaction of Pd with the α-Al₂O₃ support. The optimized Pd/α-Al₂O₃ catalyst possessed high catalytic activity and excellent stability, delivering a space–time yield (STY) of DMO of 2663 g L⁻¹ h⁻¹, which is higher than that of the active Pd-based catalysts reported so far. This strategy provides a simple way for modulating the catalytic performance and also can be extended to other industrial applications.