Synthesis and high formaldehyde sensing properties of quasi two-dimensional mesoporous ZnSnO3 nanomaterials.

Quasi two-dimensional (2D) mesoporous ZnSnO3 nanomaterials (QTMZNS) were synthesized by a simple template-free hydrothermal method. The as-prepared products were characterized by TEM, SEM, XRD, TG/DTA, and FTIR. The results showed that the precursor was a mixture of Zn5(OH)6(CO3)2 and ZnSnO3 in the hydrothermal process, and the high purity QTMZNS were obtained by calcination combined with subsequent washing of 20 wt% NH4Cl solutions. A possible growth process and mechanism of the quasi 2D mesoporous structure was proposed. Gas sensing properties of QTMZNS were investigated, and the QTMZNS-based sensors exhibited excellent gas sensing properties. When exposed to 100 ppm formaldehyde vapors, the response sensitivity is 45.8, and the concentration limit can reach as low as 0.2 ppm of formaldehyde. All these results are much better than those reported so far, which will have great potential applications for practical air quality monitoring.