ZnO/WO3 core-shell nanowires were synthesized by thermal evaporation of a mixture of ZnO and graphite powders (ZnO:C = 1:1) followed by sputter-deposition of WO3. The sensing properties of multiple networked ZnO-core/WO3-shell nanorod sensors toward H-2 gas was examined. The responses of pristine ZnO and ZnO-core/WO3-shell nanorods to 1000 ppm H-2 at room temperature under UV illumination were similar to 236% and similar to 645%, respectively. The responses of the core-shell nanowires increased from similar to 118 to similar to 645% with increasing the UV illumination intensity from 0 mW/cm(2) to 1.2 mW/cm(2). The enhanced sensing performance of the ZnO-core/WO3-shell nanowires induced by encapsulation with WO3 was explained based on a combination of surface depletion and potential barrier-controlled carrier transport models. The origin of the enhanced sensing properties of ZnO-core/WO3-shell nanorods toward H-2 under UV illumination was also discussed. (C) 2014 Elsevier B.V. All rights reserved.