Unique hole-accepting carbon-dots promoting selective carbon dioxide reduction nearly 100% to methanol by pure water

Solar-driven CO₂ reduction by water to alcohols offers a pathway to sustainable liquid fuels but is limited by sluggish water oxidation and rapid charge recombination. Using transient absorption spectroscopy, we show that microwave-synthesised carbon-dots (mCDs) act as unique hole-acceptors, extending the electron lifetime (τ) of carbon nitride (CN) by about sixfold and favouring formation of the six-electron product methanol. mCD-decorated CN achieves steady, stoichiometric O₂ and methanol generation from water and CO₂ with nearly 100% selectivity to methanol and an internal quantum efficiency of ~2.1% in the visible, corroborated by isotopic labelling. The mCDs rapidly extract holes from CN and suppress methanol adsorption, thereby prioritising water oxidation over methanol oxidation and enhancing selective CO₂ reduction to alcohols. This establishes a strategy for efficient and highly selective CO₂-to-chemicals conversion using water as the sole electron donor.

Yiou Wang, Xu Liu, Xiaoyu Han, Robert Godin, Jialu Chen, Wuzong Zhou, Chaoran Jiang, Jamie F. Thompson, K. Bayazit Mustafa, Stephen A. Shevlin, James R. Durrant, Zhengxiao Guo, Junwang Tang