Facile fabrication of highly efficient Cu/CNT catalysts by ALD technique for methanol oxidative carbonylation

Carbon nanotubes-loaded copper cluster catalysts (Cu x /CNT-ALD) were fabricated by atomic layer deposition (ALD) to achieve the construction of small-sized highly dispersed copper clusters in methanol oxidative carbonylation to synthesize dimethyl carbonate (DMC). The Cu/CNT-IMP catalyst was prepared by the traditional impregnation method for comparison. Owing to the distinctive surface self-limiting growth mechanism of the ALD method and the unique structure of CNT, the size of the copper clusters on the Cu10/CNT-ALD catalyst was controlled to about ∼0.48 nm and showed superior activity at ultra-low Cu loading of 0.21 wt%. Abundant oxygen-containing groups and defects on CNT provided stabilized Cu cluster immobilization sites, allowing the active Cu 0 sites to maintain a high concentration during the reaction. Cu 0 as the active species for the synthesis of DMC resulted in a turnover frequency of up to 141.0 h −1 on the optimal Cu10/CNT-ALD, which is about 14 times higher than that of Cu/CNT-IMP catalyst, and there was no significant inactivation after five cycles. This work offers insightful possibilities to investigate synthetic strategies for the preparation of cluster catalysts by atomic layer deposition and to improve DMC yields.