Improving H2 gas sensing with ZnMn2O4/Polypyrrole Nanocomposite

Abstract

Here we report the operation of p-p heterojunction for improving the H2 gas sensing performance of ZnMn2O4/Polypyrrole nanocomposite (PZ) at room temperature. ZnMn2O4 (ZM) with a unique cubic morphology and porous architecture was synthesized via a one-step hydrothermal method. Polypyrrole (PPy) fibers and PZs were prepared through chemical oxidative polymerization of pyrrole monomers in the absence and presence of different weight percentages (wt%) of ZM, respectively. Our findings show that the PZs consisted of microcubic ZMs with dimensions of approximately 8 μm, covered with wire-like PPy fibers. The partial protonated PPy and different wt% of microcubic ZM have a significant effect on H2 gas sensing. The response of our hand-made sensor increased with increasing wt% of ZM and gas level. The PZ samples exhibited the highest response of 1.23 (the lowest tres value of 21.6 s) at a concentration of 15000 (2500) ppm H2 gas. Furthermore, the PZ sample contains 10 wt% of ZM demonstrated excellent long-term stability in response after six months, which indicates the accuracy and reliability of the sensor. H2 gas mechanism of the PZ sensor was studied in details. The advantage of p-p heterojunction could provide a new perspective for H2 gas sensing applications.