Porous one-dimensional CuWO4-WO3 nanofibers with enhanced gas accessibility and catalytic sensitization for selective H2S sensors

Abstract

The cross-sensitivity of semiconducting metal-oxide gas sensors is the primary concern for the selective recognition of specific gas analytes for applications in environmental monitoring and disease diagnosis. Herein, we propose a facile strategy for imparting selective gas-sensing properties by simultaneously modulating the morphology and composition of the sensing layer. An electrospinning process combined with a sacrificial templating route was employed to synthesize one-dimensional (1D) metal oxide nanofibers (NFs) with heterostructures for the selective detection of hydrogen sulfide (H2S). A composite of CuWO4-WO3 NFs with mesopores and macropores was obtained by the addition of polystyrene (PS) sacrificial templates and a Cu precursor during the electrospinning of the W precursor and polyvinylpyrrolidone (PVP), followed by heat treatment at an elevated temperature. The porous CuWO4-WO3 NFs exhibited a high response (Rair/Rgas = 60.8) and selectivity toward 5 ppm of H2S at 200 °C. The improved H2S sensing properties of the porous CuWO4-WO3 NFs are attributed to the increased gas permeability facilitated by the open pores and catalytic sensitization occurring within the CuWO4 phase.