Coordination tailoring of Cu single sites on C3N4 realizes selective CO2 hydrogenation at low temperature

Tang Yang,Xinnan Mao,Lu Wang,Ying Zhang,Yong Xu,Mingyu Chu,Shize Yang,Chih-Wen Pao,Xiaoqing Huang,Xiaoping Wu

doi:10.1038/s41467-021-26316-6

Abstract

CO2 hydrogenation has attracted great attention, yet the quest for highly-efficient catalysts is driven by the current disadvantages of poor activity, low selectivity, and ambiguous structure-performance relationship. We demonstrate here that C3N4-supported Cu single atom catalysts with tailored coordination structures, namely, Cu–N4 and Cu–N3, can serve as highly selective and active catalysts for CO2 hydrogenation at low temperature. The modulation of the coordination structure of Cu single atom is readily realized by simply altering the treatment parameters. Further investigations reveal that Cu–N4 favors CO2 hydrogenation to form CH3OH via the formate pathway, while Cu–N3 tends to catalyze CO2 hydrogenation to produce CO via the reverse water-gas-shift (RWGS) pathway. Significantly, the CH3OH productivity and selectivity reach 4.2 mmol g–1 h–1 and 95.5%, respectively, for Cu–N4 single atom catalyst. We anticipate this work will promote the fundamental researches on the structure-performance relationship of catalysts.

Highlights

CO2 hydrogenation has attracted great attention, yet the quest for highly-efficient catalysts is driven by the current disadvantages of poor activity, low selectivity, and ambiguous structureperformance relationship
C3N4 supported Cu SACs were synthesized via the thermal pyrolysis of melamine
Transmission electron microscopy (TEM) image shows that the as-prepared C3N4 displays a morphology of nanosheet (Supplementary Fig. 2)

Summary

Introduction

CO2 hydrogenation has attracted great attention, yet the quest for highly-efficient catalysts is driven by the current disadvantages of poor activity, low selectivity, and ambiguous structureperformance relationship. The atomic ratios of Cu in Cu–N4 and Cu–N3 SACs are 12.1% and 13.1%, respectively (Supplementary Fig. 3), which are close to those values from ICP-AES measurement (Supplementary Table 1). No obvious differences in the XRD patterns of Cu–N4 and Cu–N3 SACs are attributed to the isolated state of Cu atom (red and blue curves in Supplementary Fig. 5).

Results

Conclusion