Facile Synthesis of Pt-Functionalized Meso/Macroporous SnO₂ Hollow Spheres through in Situ Templating with SiO₂ for H₂S Sensors

Abstract

Although single-nozzle electrospraying seems a versatile technique in the synthesis of spherical semiconducting metal oxide structures, the synthesized structures find limited use in gas-sensing applications because of their thick and dense morphology, which minimizes the accessibility of their inner surfaces. Herein, unprecedented spherical SiO@SnO core-shell structures are synthesized upon calcination of single-nozzle as-electrosprayed spheres (SPs) containing tin (Sn) and silicon (Si) precursors. Subsequent etching of SiO in NaOH (pH 12) affords meso/macroporous SnO hollow spheres (HSPs) with short diffusion length (31.4 ± 3.1 nm), small crystallites (15.5 nm), and large Brunauer-Emmett-Teller surface area (124.8 m g). Apart from surface meso/macropores, diffusion of gases into porous SnO sensing layers is realized through inner interconnection of voids of the SnO HSPs into a three-dimensional network. Functionalization of the postetched SnO HSPs with platinum (Pt) nanoparticles at 0.08 wt % yields gas-sensing materials with outstanding response ( R/ R = 1.6, 10.8, and 105.1-0.1, 1, and 5 ppm of HS, respectively) and selectivity toward HS against interfering gas molecules at 250 °C. The SiO phase in the postcalcined SiO@SnO SPs acts as a sacrificial template for pore creation and crystal growth inhibition, whereas the small amount of SiO residues in HSPs enhances the selectivity.

Controlled Synthesis of Pt Doped SnO2 Mesoporous Hollow Nanospheres for Highly Selective and Rapidly Detection of 3-Hydroxy-2-Butanone Biomarker

“…The mesoporous hollow nanostructures stacked by multiple layers of SnO 2 nanosphere have a highly usable alternating and stable structure (Wang Y. et al, 2016b), which is favorable for the diffusion of gases and then effectively improve the gas sensing performance. No phases of anchored Pt nanoparticles were observed in both SEM and HRTEM micrographs, possibly due to small amount of Pt catalyst (Bulemo et al, 2018). TEM mapping of Pt doped SnO 2 nanomaterial was also conducted (Figure 4G), which notarize the existence and equidistributional of only Sn, O, and Pt component.…”

Facile Synthesis of Hierarchical Tin Oxide Nanoflowers with Ultra-High Methanol Gas Sensing at Low Working Temperature

“…SnO 2 gas sensors attract attention of researchers due to their simple and low-cost synthesis method and room temperature operation. The huge improvement of gas sensing performance has been achieved by decreasing crystallite size [4, 5], doping by metal elements [6, 7], fabricating heterostructure of metal oxide [8, 9], and, especially, fabricating hierarchical structure [10, 11]. To date, a variety of gas sensors has been proposed to improve gas sensing to methanol, such as In 2 O 3 porous nanospheres [12], three-dimensionally macroporous LaFeO 3 [13], and aluminum-mesoporous silicon coplanar [14].…”

An effective H2S sensor based on SnO2 nanowires decorated with NiO nanoparticles by electron beam evaporation

“…12 However, this material shows relatively low sensitivity to H 2 S gas; thus, numerous attempts have been made to enhance its performance. [13][14][15][16] Enhancement of gassensing performance of metal oxides by doping 17 or surface decoration is an effective method because it can utilise the advantages of surface modulation and high catalytic activity of decorated materials. 18,19 Noble metals are generally used as decorative materials to enhance gas sensing performance, but they are expensive, leading to high cost of products.…”

“…18,19 Noble metals are generally used as decorative materials to enhance gas sensing performance, but they are expensive, leading to high cost of products. 14,20 Using other abundant materials to functionalise the surface of SnO 2 to enhance its sensing performance has becomes one of the priorities in recent years. 21,22 The common materials used to functionalise the surface of n-type SnO 2 to enhance H 2 S sensing performance include p-type semiconductors, such as CuO and nickel oxide (NiO); these materials are applied to utilise the synergic effects of p-n heterojunction and catalytic activity of decorated materials.…”