The present report investigates hydrogen gas sensing properties on PAN/(PAN-b-PMMA) derived electrospun nanoporous carbon nanofibers loaded on ZnO nanostructures. Polymer blend of PAN and PAN-b-PMMA is used to obtain the high surface area porous CNF which improve further sensing performance. Moreover, a facile technique such as drop cast method is used to load the CNF (0.1–0.5 wt%) on Au pattern interdigitated electrodes over ZnO nanostructures. Loading of CNF was optimized to ensure proper connection between the electrodes over ZnO surface, which was measured using I–V characteristics. Initially, current decreased for less amount of CNF (0.1–0.2 wt%), which later increased for high concentration of CNF (0.3–0.5 wt%). It was further observed that 0.2 wt% CNF/ZnO nanostructures based sensor exhibited maximum sensing response (73.54%) as compared to CNF (3.29%) and ZnO (44.51%) for 100 ppm hydrogen at 150 °C. This enhanced sensing response may be attributed to diffusion of hydrogen molecules through the nanoporous CNF, thus enabling the formation of p - n heterojunction at the interface of CNF and ZnO. The presence of oxygen functional groups on CNF surface also contributes to the enhancement of the sensing performance. © 2019 Elsevier B.V.