Triethanolamine-assisted photodeposition of non-crystalline CuxP nanodots for boosting photocatalytic H2 evolution of TiO2

Abstract

Exploiting highly efficient, noble metal-free, and ultra-small H₂-evolution cocatalysts is crucial to promoting the photocatalytic water splitting reaction. Herein, ultra-small non-crystalline Cu_xP nanodots (Cu_xP-ND) as an efficient H₂-evolution cocatalyst were coupled on the TiO₂ surface via a simple triethanolamine (TEOA)-assisted photodeposition strategy. Owing to the initially uniform anchoring of the Cu(TEOA)²⁺ precursor on the TiO₂ surface, the final Cu_xP nanodots show a very small size of 2–5 nm and are homogeneously distributed on the surface of the photocatalyst. The obtained Cu_xP-ND/TiO₂ photocatalysts displayed a significantly enhanced ultraviolet-light H₂-production activity and the Cu_xP-ND/TiO₂(1 wt%) sample displayed a maximum hydrogen-production rate of 93.5 μmol h⁻¹ with an apparent quantum efficiency of 7.7%, which is a 30-fold increase compared to bare TiO₂. The boosted hydrogen generation can be ascribed to the fact that the ultra-small non-crystalline Cu_xP nanodots can not only induce the formation of a built-in electric field to improve the rapid transfer of photogenerated electrons, but also provide interfacial hydrogen-production sites to dramatically enhance the H₂-generation rate. These new non-crystalline Cu_xP nanodots with a green and facile preparation procedure can pave a new way to exploit efficient co-catalysts for photocatalytic hydrogen evolution.