Microwave-assisted growth of In₂O₃ nanoparticles on WO₃ nanoplates to improve H₂S-sensing performance

Abstract

Hierarchical In 2 O 3 @WO 3 nanocomposites, consisting of discrete In 2 O 3 nanoparticles (NPs) on singlecrystal WO 3 nanoplates, were synthesized via a novel microwave-assisted growth of In 2 O 3 NPs on the surfaces of WO 3 nanoplates that were derived through an intercalation and topochemical-conversion route. The techniques of XRD, SEM, TEM and XPS were used to characterize the samples obtained. The gas-sensing properties of In 2 O 3 @WO 3 nanocomposites, together with WO 3 nanoplates and In 2 O 3 nanoparticles, were comparatively investigated using inorganic gases and organic vapors as the target substances, with an emphasis on H 2 S-sensing performance under low concentrations (0.5-10 ppm) at 100-250 C. The results show that the In 2 O 3 NPs with a size range of 12-20 nm are uniformly anchored on the surfaces of the WO 3 nanoplates. The amounts of the In 2 O 3 NPs can be controlled by changing the In 3+ concentrations in their growth precursors. The In 2 O 3 @WO 3 (In/W ¼ 0.8) sample has highest H 2 S-sensing performance operating at 150 C; its response to 10 ppm H 2 S is as high as 143, 4 times higher than that of WO 3 nanoplates and 13 times that of In 2 O 3 nanocrystals. However, the responses of the In 2 O 3 @WO 3 sensors are less than 13 upon exposure to 100 ppm of CO, SO 2 , H 2 , CH 4 and organic vapors, operating at 100-150 C. The improvement in response and selectivity of the In 2 O 3 @WO 3 sensors upon exposure to H 2 S molecules can be attributed to the synergistic effect of In 2 O 3 NPs and WO 3 nanoplates, hierarchical microstructures and multifunctional interfaces.

Ultrasensitive and low detection limit of acetone gas sensor based on W-doped NiO hierarchical nanostructure

“…The W 4f specturm (Fig. 4c) was composed of two obvious peaks at 36.0 and 37.9 eV, belonging to W 4f 7/2 and W f 5/2 of WO 3 , respectively [9]. The O 1s peak was asymmetric and could be fitted into two components.…”

“…Resistive gas sensors based on metal oxide semiconductors such as SnO 2 [1,2], ZnO [3,4], TiO 2 [5,6], WO 3 [7][8][9][10][11][12], In 2 O 3 [13,14], α-Fe 2 O 3 [15], and NiO [16] occupy the significant positions in the field of gas sensors for monitoring and detecting inflammable, explosive, or toxic gases due to the advantages of low cost, simple operation and portability. Extensive research efforts have been committed to develop high-performance gas sensors with high sensitivity and low detection limit [17].…”

Low-temperature solvothermal synthesis of hierarchical flower-like WO3nanostructures and their sensing properties for H2S

“…9 As an n-type wide band-gap (2.6-3.2 eV) semiconductor, tungsten trioxide (WO 3 ) has been widely studied and found that exhibited considerably application prospects in the field of detecting hazardous gases. [10][11][12][13][14][15][16] In the past few years, WO 3 -based sensors with different morphologies have been prepared using various techniques such as CVD, template-carbonization, sputtering, sol-gel, pyrolysis, and hydrothermal. [17][18][19][20][21][22] However it still remains a significant challenge to develop a facile method to prepare shape-controlled hierarchical WO 3 -based sensors with better performance from low-dimensional nanocrystals via selfassembly.…”

Incorporation of Ag-In 2 O 3 nanostructures into sodium borosilicate glass: A combined route for high transparency and fluorescence

“…3(b), could originate from IneO bond or AgeO bond. Some reports [36,37] ascribed the similar peak position to the lattice oxygen in IneOeIn bonds of In 2 O 3 species. In this paper, the high-resolution Ag 3d core level spectrum shows two XPS peaks at 374.1 eV and 368.1 eV in Fig.…”