Low-temperature H2S sensors based on Ag-doped α-Fe2O3 nanoparticles

Abstract Ag-doped α-Fe 2 O 3 nanoparticles were synthesized by a chemical coprecipitation method and characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and high-resolution TEM (HRTEM), thermogravimetry-differential thermal analysis (TG-DTA), X-ray photoelectron spectroscopy (XPS) and Brunauer–Emmett–Teller specific surface area analysis (BET) techniques. Obtained results indicated that spherical Ag grains with size of about 5 nm are highly dispersed on the surface of α-Fe 2 O 3 nanoparticles. The surface area of the Ag/Fe 2 O 3 nanoparticles is several times as large as that of pure α-Fe 2 O 3 . The H 2 S sensing properties of these Ag/Fe 2 O 3 sensors were systematically investigated. In comparison with pure α-Fe 2 O 3 , all of the Ag-doped sensors showed better sensing performance in respect of response, selectivity and optimum operating temperature. The effects of Ag content, calcination and operation temperature on the sensing characteristics of the Ag/α-Fe 2 O 3 sensors were also investigated. The sensor containing 2 wt% Ag and calcined at 400 °C exhibited the maximum response to H 2 S at 160 °C. A possible mechanism for the influence of Ag on the H 2 S-sensing properties of Ag/α-Fe 2 O 3 sensors was proposed.

[1]  M. Haruta,et al.  Development of carbon monoxide detector using Au fine particles-doped α-Fe2O3 , 1993 .

[2]  Baolin Zhu,et al.  Synthesis and characterization of Pd-doped α-Fe2O3 H2S sensor with low power consumption , 2007 .

[3]  Peidong Yang,et al.  Photochemical sensing of NO(2) with SnO(2) nanoribbon nanosensors at room temperature. , 2002, Angewandte Chemie.

[4]  Tong Maosong,et al.  Surface modification of oxide thin film and its gas-sensing properties , 2001 .

[5]  G. Shen,et al.  Hydrogen sulfide sensing properties of NiFe2O4 nanopowder doped with noble metals , 2004 .

[6]  Chu Xiangfeng,et al.  Ethanol gas sensor based on CoFe2O4 nano-crystallines prepared by hydrothermal method , 2006 .

[7]  Udo Weimar,et al.  Analysis of the noble metal catalytic additives introduced by impregnation of as obtained SnO2 sol–gel nanocrystals for gas sensors , 2000 .

[8]  János Mizsei,et al.  Structural studies of sputtered noble metal catalysts on oxide surfaces , 1998 .

[9]  G. Dai,et al.  A study of the sensing properties of thin film sensor to trimethylamine , 1998 .

[10]  G. Rao,et al.  Gas sensitivity of ZnO based thick film sensor to NH3 at room temperature , 1999 .

[11]  Kaidong Han,et al.  Low-temperature CO oxidation over CuO/Fe2O3 catalysts , 2007 .

[12]  C. Leonelli,et al.  Syntheses of Fe2O3/Silica Red Inorganic Inclusion Pigments for Ceramic Applications , 1998 .

[13]  G. N. Chaudhari,et al.  Characterization of nanosized TiO2 based H2S gas sensor , 2006 .

[14]  V. V. Malyshev,et al.  Gas sensitivity of semiconductor Fe2O3-based thick-film sensors to CH4, H2, NH3 , 1994 .

[15]  H Zhao,et al.  Sol–gel route to pseudocubic shaped α-Fe2O3 alcohol sensor: preparation and characterization , 2005 .

[16]  Huijing Jiang,et al.  A highly selective chemiluminescent H2S sensor , 2004 .

[17]  Martin Moskovits,et al.  Detection of CO and O2 Using Tin Oxide Nanowire Sensors , 2003 .

[18]  S. Chaudhuri,et al.  Synthesis of a α-Fe2O3 nanocrystal in its different morphological attributes: growth mechanism, optical and magnetic properties , 2007 .

[19]  Baolin Zhu,et al.  H2S sensing characteristics of Pt-doped α-Fe2O3 thick film sensors , 2007 .

[20]  Jun Chen,et al.  α‐Fe2O3 Nanotubes in Gas Sensor and Lithium‐Ion Battery Applications , 2005 .

[21]  To the theory of semiconductor gas sensors , 1998 .

[22]  Jiaqiang Xu,et al.  Hydrothermal synthesis of In2O3 for detecting H2S in air , 2006 .

[23]  Daihua Zhang,et al.  In2O3 nanowires as chemical sensors , 2003 .

[24]  J. Chai,et al.  Ethanol sensors based on nano-sized α-Fe2O3 with SnO2, ZrO2, TiO2 solid solutions , 2003 .

[25]  P. L. Silveston,et al.  Surface characterisation of Pd–Ag/Al2O3 catalysts for acetylene hydrogenation using an improved XPS procedure , 2004 .

[26]  Xiaoming Sun,et al.  Highly sensitive WO3 hollow-sphere gas sensors. , 2004, Inorganic chemistry.

[27]  L. A. Patil,et al.  Surface modified BaTiO3 thick film resistors as H2S gas sensors , 2006 .

[28]  R. Brand,et al.  The crucial role of particle morphology in the magnetic properties of haematite , 1999 .

[29]  Min-Hsiung Hon,et al.  The effects of thickness and operation temperature on ZnO:Al thin film CO gas sensor , 2002 .

[30]  Naoto Koshizaki,et al.  Sensing characteristics of ZnO-based NOx sensor , 2000 .

[31]  L. Caputi,et al.  HREELS study of Au/Fe2O3 thick film gas sensors , 2001 .