Forming multiple heterojunctions in ZnO/Cu/Cu2O boosts dimethyldichlorosilane production in Rochow-Müller reaction

Abstract

Forming heterojunctions in catalysts is an effective way to modulate their electronic structures and catalytic performance. However, this strategy is rarely applied to thermal catalysis. Herein, the ZnO/Cu/Cu2O catalysts with different metallic Cu contents and both Schottky and P-N heterojunctions were prepared by simply reducing ZnO/Cu2O with CO and investigated for their electronic effects on the catalytic property in the Rochow-Müller reaction. The ZnO/Cu/Cu2O catalyst with an optimal content of metallic Cu exhibited a much-enhanced catalytic activity towards the targeted product of dimethyldichlorosilane. Detailed characterizations and theoretical calculations showed that the formation of the Schottky junction between Cu and ZnO promotes electron transfer at the P-N heterojunction between Cu2O and ZnO, leading to enhanced reduction of Cu+ into active Cu atoms and the ultimate formation of the Cu3Si active phase. This work provides a new fundamental understanding of the electron structure effect on catalysis and a strategy to design highly efficient heterogeneous catalysts for the Rochow-Müller reaction.