In situ self-exsolved ultrasmall Fe ₂ P quantum dots from attapulgite nanofibers as superior cocatalysts for solar hydrogen evolution

Developing highly active, stable, and cost-efficient cocatalysts for photocatalytic H₂ evolution is pivotal in the area of renewable energy conversion. Herein, we present a straightforward, low-temperature phosphidation strategy for in situ exsolving doped Fe ions from natural attapulgite (ATP) nanofibers into a supported Fe₂P cocatalyst for the photocatalytic H₂ evolution reaction (HER). The resulting Fe₂P QDs/ATP features highly dispersed Fe₂P QDs with an average size of <2 nm and a strong interfacial interaction between self-exsolved Fe₂P QDs and the ATP substrate, thus providing ample and stable active sites for the photocatalytic HER. When employed as a cocatalyst, Fe₂P QDs/ATP exhibits superior catalytic activity and notable stability in a molecular system with low-cost xanthene dyes as the photosensitizer under visible light irradiation. More importantly, Fe₂P QDs/ATP can also efficiently and stably catalyze the photocatalytic HER when simply combined with various semiconductor photocatalysts (g-C₃N₄, TiO₂, and CdS). This strategy of exsolving transition metal ions from substrates is an effective yet simple approach for the development of highly active supported HER cocatalysts for renewable and clean energy conversion.