From E-Waste to Nb-Pb Co-Doped and Pd-Loaded TiO2 /BaTiO3 Heterostructure: Highly Efficient Photocatalytic Performance.

A new and sustainable process was reported for the in situ synthesis of Nb-Pb co-doped and Pd-loaded TiO2 /BaTiO3 nanometer heterostructures from waste multilayer ceramic capacitors through a simple chlorination-leaching route. The particle size of the Nb-Pb co-doped heterostructure and the Pd loading were 20-50 nm and less than 5 nm, respectively. The bandgaps of the prepared samples were in the range 2.81-2.92 eV. The optimal simulated-sunlight photocatalytic H2 production rate and Rhodamine B degradation rate of the prepared heterostructure could reach 576.8 μmol g-1  h-1 and 0.29911 min-1 , respectively, which were approximately 11.3 and 19.1 times higher than those of commercial TiO2 , and 5.96 and 8.91 times higher than those of bare TiO2 /BaTiO3 . The recycled heterostructure exhibited excellent photostability and reusability. Such superior photocatalytic performance of the sample was attributed to the formation of the heterostructure, the Nb-Pb co-doping, and the Pd loading, which enhanced the visible light absorption and charge separation efficiency. Furthermore, DFT calculations were applied to explore the enhanced mechanism. This study demonstrates a sustainable process for the conversion of e-waste to a high-value-added and highefficiency photocatalyst, which has the advantages of waste utilization, low-cost preparation, and environmental protection.