Synergy of nanocrystalline carbon nitride with Cu single atom catalyst leads to selective photocatalytic reduction of CO2 to methanol

LeMercier, Tara M.; Thangamuthu, Madasamy; Kohlrausch, Emerson C.; Chen, Yifan; Stoppiello, Craig T.; Fay, Michael W.; Rance, Graham A.; Aliev, Gazi N.; Theis, Wolfgang; Biskupek, Johannes; Kaiser, Ute; Lanterna, Anabel E.; Alves Fernandes, Jesum; Khlobystov, Andrei N.

Abstract

Carbon nitride (C3N4) possesses both a band gap in the visible range and a low-lying conduction band potential, suitable for water splitting and CO2 reduction reactions (CO2RR). Yet, bulk C3N4 (b-C3N4) suffers from structural disorder leading to sluggish reaction kinetics. This can be improved by graphitisation; however, current processes in the literature, lead to a variety of graphitised C3N4 (g-C3N4), making it difficult to link the degrees of graphitisation with the functional properties. Herein, we employ complementary analyses, including electrochemical impedance, photoluminescence, and photocurrent, to elucidate structure–property–function relationships. Guided by the descriptors, we developed a facile two-step annealing method that yields nanocrystalline carbon nitride (nc-C3N4), comprising nanoscale graphitic domains within an amorphous matrix. The nanocrystalline grains of nc-C3N4 allow effective immobilisation of Cu atoms and stabilisation of low oxidation states (Cu(I)). Electron microscopy and energy-dispersive X-ray spectroscopy demonstrate that Cu is atomically dispersed. Importantly, the addition of only 0.11 wt% of copper to nc-C3N4 drastically decreases the charge recombination and resistance to change transfer. The synergy of the Cu single-atom catalyst and nanocrystalline domains in carbon nitride (Cu/nc-C3N4) leads to a remarkable 99% selectivity towards methanol production with a rate of 316 μmol gcat−1 h−1 during the photocatalytic CO2RR, which is absent in Cu/b-C3N4.

Citation

LeMercier, T. M., Thangamuthu, M., Kohlrausch, E. C., Chen, Y., Stoppiello, C. T., Fay, M. W., Rance, G. A., Aliev, G. N., Theis, W., Biskupek, J., Kaiser, U., Lanterna, A. E., Alves Fernandes, J., & Khlobystov, A. N. (2024). Synergy of nanocrystalline carbon nitride with Cu single atom catalyst leads to selective photocatalytic reduction of CO2 to methanol. Sustainable Energy and Fuels, 1691-1703. https://doi.org/10.1039/D4SE00028E

• Journal Article Type: Article
• Acceptance Date: Mar 6, 2024
• Online Publication Date: Mar 6, 2024
• Publication Date: Apr 21, 2024
• Deposit Date: Apr 8, 2024
• Publicly Available Date: Apr 9, 2024
• Journal: Sustainable Energy and Fuels
• Print ISSN: 2398-4902
• Electronic ISSN: 2398-4902
• Publisher: Royal Society of Chemistry
• Peer Reviewed: Peer Reviewed
• Issue: 8
• Pages: 1691-1703
• DOI: https://doi.org/10.1039/D4SE00028E
• Keywords: Energy Engineering and Power Technology; Fuel Technology; Renewable Energy, Sustainability and the Environment
• Public URL: https://nottingham-repository.worktribe.com/output/33027568
• Publisher URL: https://pubs.rsc.org/en/content/articlelanding/2024/se/d4se00028e