Enhanced room-temperature humidity sensing performance of SnO2/MOF-303 nanocomposites with SnO2 loading

SnO 2 /MOF-303 nanocomposites were synthesized via a wet impregnation method. • SnO 2 nanoparticles were well-dispersed in the mesopores of SnO 2 /MOF-303 nanocomposites. • SnO 2 nanoparticles greatly enhanced the humidity sensitivity of SnO 2 /MOF-303 sensors. • The response/recovery times and humidity hysteresis of 16.7SnM sensor are favorable. • This improvement came from the synergistic effect between the proton and electron transport. Mesoporous MOF-303 was synthesized via a hydrothermal method using H 3 PDC and AlCl 3 as precursors. Subsequently, SnO 2 nanoparticles were incorporated into the micropores of MOF-303 through a wet impregnation process, yielding the SnO 2 /MOF-303 nanocomposite. The nitrogen atoms within the MOF-303 framework form strong coordination interactions with Sn 4+ , effectively anchoring the SnO 2 species within the micropores. This nano-confinement effect further promotes the formation of SnO 2 nanoparticles at low temperatures. Morphological and microstructural characterization confirmed that the SnO 2 nanoparticles were uniformly dispersed within the SnO 2 /MOF-303 nanocomposite and primarily located in the micropores. Humidity-sensing measurements demonstrated that the incorporation of SnO 2 nanoparticles significantly enhanced the humidity sensitivity of the SnO 2 /MOF-303 sensor at room temperature. Among the four sensors prepared in this study, the 16.7SnM sensor (with a nominal SnO 2 content of 16.7 wt% in the precursor solution) exhibited the highest humidity sensitivity, the fastest response and recovery times, the lowest hysteresis, and excellent long-term stability. This substantial improvement in humidity-sensing performance is attributed to the synergistic effect between proton and electron transport, arising from the increased oxygen vacancies introduced by the SnO 2 nanoparticles. The outstanding performance of the 16.7SnM sensor presents a promising strategy for the development of high-performance humidity sensors Download: Download high-res image (231KB) Download: Download full-size image