Phase transition effect on durability of WO3 hydrogen sensing films: An insight by experiment and first-principle method

Utilizing experimental methods, we have identified that the phase transition of WO3 from edge-sharing into corner-sharing can largely decrease the bleaching velocity during hydrogen sensing cycles. This phase transition was successfully prevented by the addition of silica and the gas sensing cycles of WO3/SiO2 film have been undertaken more than 500 times without any obvious property attenuation. The first principles calculations suggest a tendency of WO3 from clusters into cross-link network. During this process, the HOMO–LUMO gap of WO3 decreases as well as the hydrogen atom desorption energy, which indicates a decay of the bleaching velocity.