Coupling Cu+ species and Au nanoparticles on ZnO nanosheets for robust ethanol sensing.

Bimetal decoration on ZnO-based sensing materials can effectively improve their sensing performance, while the synergistic effect and structure-activity relationships of each element is still ambiguous. Herein, we have successfully synthesized Au nanoparticles decorated Cux+-doped ZnO porous nanosheets (Au/Cu-ZnO) with a larger specific surface area, distinct surface and electronic structure, and the prepared sensors exhibit excellent gas sensing performance for ethanol. Notably, Au/Cu-ZnO sensors display superior sensing response (R a /R g =95.45) to 50 ppm ethanol at 160 °C, which is 2.91, 2.45 and 9.31 folds than Au-ZnO, Cu-ZnO and ZnO, the sensors also exhibit low limit of detection (172.5 ppb), fast recovery (34 s) and high selectivity. Several characterizations and DFT calculations reveal that the downshifts of the d -band center can be observed after Cu immobilized, which greatly optimize the adsorption and desorption behavior. Additionally, the introduction of Cu facilitates the formation of oxygen vacancy, endowing the materials with more amount of high mobility O- (ad) species, which contributes to the enhanced sensing performance. This work provides new insights for the designation of high-performance sensing materials and deep investigation of sensing mechanisms. • The Au/Cu-ZnO has been successfully prepared by a simple method. • The sensors show superior gas sensing performance to ethanol. • The introduction of Cu facilitates the formation of oxygen vacancy and the downshifts of d -band center. • Bimetal co-catalysis effect improve sensing performance. [ABSTRACT FROM AUTHOR]