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

Solar-driven CO₂ reduction by abundant water to alcohols can supply sustainable liquid fuels and alleviate global warming. However, the sluggish water oxidation reaction has been hardly reported to be efficient and selective in CO₂ conversion due to fast charge recombination. Here, using transient absorption spectroscopy, we demonstrate that microwave-synthesised carbon-dots (^mCD) possess unique hole-accepting nature, prolonging the electron lifetime (t_50%) of carbon nitride (CN) by six folds, favouring a six-electron product. ^mCD-decorated CN stably produces stoichiometric oxygen and methanol from water and CO₂ with nearly 100% selectivity to methanol and internal quantum efficiency of 2.1% in the visible region, further confirmed by isotopic labelling. Such ^mCD rapidly extracts holes from CN and prevents the surface adsorption of methanol, favourably oxidising water over methanol and enhancing the selective CO₂ reduction to alcohols. This work provides a unique strategy for efficient and highly selective CO₂ reduction by water to high-value chemicals.