A Co<sub>3</sub>O<sub>4</sub>-CDots-C<sub>3</sub>N<sub>4</sub> three component electrocatalyst design concept for efficient and tunable CO<sub>2</sub> reduction to syngas.

Guo, Sijie; Zhao, Siqi; Wu, Xiuqin; Li, Hao; Zhou, Yunjie; Zhu, Cheng; Yang, Nianjun; Jiang, Xin et al. · Nat Commun · 2017

basic_science · Level V

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Abstract

Syngas, a CO and H<sub>2</sub> mixture mostly generated from non-renewable fossil fuels, is an essential feedstock for production of liquid fuels. Electrochemical reduction of CO<sub>2</sub> and H<sup>+</sup>/H<sub>2</sub>O is an alternative renewable route to produce syngas. Here we introduce the concept of coupling a hydrogen evolution reaction (HER) catalyst with a CDots/C<sub>3</sub>N<sub>4</sub> composite (a CO<sub>2</sub> reduction catalyst) to achieve a cheap, stable, selective and efficient route for tunable syngas production. Co<sub>3</sub>O<sub>4</sub>, MoS<sub>2</sub>, Au and Pt serve as the HER component. The Co<sub>3</sub>O<sub>4</sub>-CDots-C<sub>3</sub>N<sub>4</sub> electrocatalyst is found to be the most efficient among the combinations studied. The H<sub>2</sub>/CO ratio of the produced syngas is tunable from 0.07:1 to 4:1 by controlling the potential. This catalyst is highly stable for syngas generation (over 100 h) with no other products besides CO and H<sub>2</sub>. Insight into the mechanisms balancing between CO<sub>2</sub> reduction and H<sub>2</sub> evolution when applying the HER-CDots-C<sub>3</sub>N<sub>4</sub> catalyst concept is provided.