Dual rare earth atomic sites with a conjugated electronic structure for efficient photocatalytic water splitting

The surface active sites of semiconductor materials are crucial for achieving excellent photocatalytic performance. Herein, Eu and Ce dual rare-earth metal atomic active sites with a conjugated electronic structure were constructed on the surface of B-doped TiO₂ through an atomic confinement strategy. Under the optimized conditions, the as-prepared photocatalyst (CeEu-BTO) achieved hydrogen evolution rates of 558.6 μmol g^-1 h^-1 (freshwater) and 232.7 μmol g^-1 h^-1 (seawater) with apparent quantum yields (AQYs) of 22.17% and 5.07%, respectively. The experimental and density functional theoretical calculation results suggested that the excellent photocatalytic activity of CeEu-BTO primarily stemmed from the boron-bridged Ce and Eu atomic active sites (Ce-B-Eu) that have strong electronic interactions with TiO₂. The formed Ce-B-Eu active sites can broaden light absorption, improve the separation efficiency of photogenerated carriers, and reduce the activation barriers for H⁺ reduction. This work provides a new strategy for the design of efficient rare earth metal-coupled semiconductor photocatalysts.