Selective sensing performance of UV-activated ZnO nanowires decorated with Ir and Rh nanoparticles

Single-crystal zinc oxide (ZnO) nanowires (NWs) were synthesized through self-assembly hydrothermal reaction and decorated with oxidative and reductive catalytic active sites to tailor their gas sensing selectivity. The sensing performances of the developed materials were investigated under ultraviolet-light emitting diode (UVLED) irradiation against low concentrations of nitrogen dioxide (NO2) and ammonia (NH3) gases, as oxidizing and reducing gas representatives, respectively. The growth of NWs towards the hexagonal c-axis was demonstrated, where presence of Rh3d and Ir4f active sites on the surface of ZnO NWs was observed. The sensing performance of the surface modified ZnO NWs was enhanced significantly, compared with that of the pristine ZnO NWs. The Rh-decorated ZnO NWs sensor exhibited superior performance in the detection of NO2, while the Ir sites promoted the oxidative reaction in the presence of NH3, attributed to the Fermi level of the metaldecorated films under UV irradiation.

Automated summary

Single-crystal zinc oxide nanowires were synthesized and decorated with catalytic active sites to tailor their gas sensing selectivity. The sensing performances of the materials were investigated under UVLED irradiation against low concentrations of NO2 and NH3 gases. The surface modified ZnO nanowires exhibited significantly enhanced sensing performance, with Rh-decorated ZnO NWs showing superior detection of NO2 and Ir sites promoting the oxidative reaction in the presence of NH3.