An isolation strategy to anchor atomic Ni or Co cocatalysts on TiO₂(A) for photocatalytic hydrogen production

TiO₂ has been considered as an ideal photocatalyst for water splitting. However, narrow light absorbance, low charge separation efficiency, and rare surface active sites lead to the low photocatalytic efficiency of TiO₂. Although extensive research attempted to improve the situation, there is still lack of method for constructing high active and noble-metal-free TiO₂ photocatalyst for H₂ evolution reactions (HER). In this work, we loaded single atomic (SA) Ni (or Co) on the surface of anatase TiO₂ (TiO₂(A)) nanosheets by an isolation strategy. Ethylene diamine tetraacetic acid and ethylene glycol (EDTA-EG) compounds were used to chelate metal ions in solution and form carbon quantum dots in the following thermal treatment to isolate the metal ions on surface of TiO₂(A). The prepared Ni SA/TiO₂(A) catalyst owned a “skin wrapped body” structure with in-situ formed two-dimensional (2D) heterojunction facilitating the fast electron transfer. As a result, the Ni SA/TiO₂(A) catalyst showed a high H₂ evolution rate of 2,900 μmol·g⁻¹·h⁻¹. This work provides an isolation strategy for constructing promising single-atom metal catalyst for photocatalysis and beyond.