The controllable synthesis and enhanced gas sensing performances of AuNP-modified ZnSnO3 hollow nanocubes toward highly sensitive toluene detection

Morphology control and noble-metal modification have become effective ways to improve the gas sensing performances of mixed-metal-oxide sensors. In this study, ZnSnO3 nanocube structures with different morphologies were synthesized via combining NaOH-assisted dissolution and a calcination process, and they were then modified with various amounts of Au nanoparticles through a chemical reduction method. Some important parameters were systematically investigated to optimize the gas sensing performance toward toluene detection. Noticeably, the as-prepared Au2NPs@ZnSnO3 hollow nanocube sensor exhibits an ultra-high response (80.82@100 ppm), fast response and recovery times (11 s/12 s, respectively), a low limit of detection (10 ppb), excellent repeatability, long-term stability, and good anti-humidity properties. The enhanced gas sensing mechanism of the Au2NPs@ZnSnO3 sensor is also thoroughly discussed, which can be attributed to the unique hollow nanocube structure and the excellent electron sensitization and chemical sensitization properties of AuNPs. As a result, the optimum AuNP-modified ZnSnO3 sensing material is promising for high-sensitivity toluene detection for practical applications.