A rational design of hollow nanocages Ag@CuO-TiO2 for enhanced acetone sensing performance

Hollow nanostructured Ag@CuO-TiO2 was prepared by a facile hydrothermal method with high surface area and uniform catalyst functionalization. The obtaining of Ag@CuO-TiO2 multicomponent hollow nanocages was ascribed to the addition of TiF4, which serves as both the precursor of TiO2 and etching agent by releasing HF. In this process, Cu2O works as the self-template and the scaffold to induce and maintain the shape of hollow nanocages. Therefore, the formation of hollow structure and multicomponent heterostructures were accomplished without tedious processes and additional template. The deposition of TiO2 layer, anchored to the Ag@Cu2O surface, avoids the aggregation of p-type or n-type nanoparticles and ultimately formation of p-p junctions or n-n junctions, which would be valuable in terms of reproducibility and scalable production. The numerous heterojunctions of CuO-TiO2, well-dispersed nanoscale Ag catalysts and hollow nanocage structures are favorable for the development of high-performance gas sensors. The desired Ag@CuO-TiO2 hollow nanocages were investigated for response to various target gases, which showed a superior sensing performance towards acetone. The improved sensing properties might be ascribed to the synergistic effects of both hollow structure and different nanocomponents.