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

[Display omitted] • ZnO/Cu/Cu 2 O catalysts with different Cu contents at the interface are prepared. • Both Schottky junctions and P-N heterojunctions are generated in ZnO/Cu/Cu 2 O catalysts. • ZnO/Cu/Cu 2 O with an optimal portion of Cu exhibits higher catalytic activity. • Schottky heterojunctions can promote electron transfer at P-N heterojunctions. 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/Cu 2 O catalysts with different metallic Cu contents and both Schottky and P-N heterojunctions were prepared by simply reducing ZnO/Cu 2 O with CO and investigated for their electronic effects on the catalytic property in the Rochow-Müller reaction. The ZnO/Cu/Cu 2 O 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 Cu 2 O and ZnO, leading to enhanced reduction of Cu+ into active Cu atoms and the ultimate formation of the Cu 3 Si 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. [ABSTRACT FROM AUTHOR]