Atomic engineering of trace endogenous Fe within natural clays into a self-supported Fe₁-P single-atom cocatalyst for photocatalytic hydrogen evolution

Mass and cost-effective synthesis of active and stable single-atom cocatalysts is vital for the development of efficient photocatalysts for sustainable H2 evolution from water splitting but remains changeling. In this work, we report on the atomic engineering of trace endogenous Fe within the lattice of natural halloysite nanotubes (HNTs) toward a self-supported Fe₁-P single-atom cocatalyst (Fe₁-P/HNTs) via a facile low-temperature phosphidation method without using external high-purity metal precursors and supports. As a result of the formation of abundant Fe₁-P active sites and the strong self-confinement effect of HNTs, the as-synthesized Fe₁-P/HNTs cocatalyst exhibits high H2 evolution activity and stability in the dye-sensitized systems under visible light. More significantly, the Fe₁-P/HNTs cocatalyst can also efficiently catalyze the H2 evolution when coupled with CdS under visible light, showing its excellent versatility under different applciation scenarios. This work provides a new staggery for the development of cost-effective single-atom cocatalysts by upgrading endogenous metal species within abundant natural resources for sustainable solar H2 evolution.