Gas Sensors Based on <I>α</I>-Fe<SUB>2</SUB>O<SUB>3</SUB> Nanorods, Nanotubes and Nanocubes

Abstract

Nanorods, nanotubes, and nanocubes of alpha-Fe2O3 were synthesized via a hydrothermal process and subsequent calcination treatment. The typical nanorod has about 71 nm in width, 7 nm in thickness, and 314 nm in length. The nanotube has outer diameter of 90-110 nm, inner diameter of 40-80 nm, and lengths of 250-400 nm. The nanocubes are rhombus cubes with an edge length of about 680 nm. The nanorods, nanotubes and nanocubes were fabricated into chemiresistive sensors. The responses (R(a)/R(g)) of the nanotube sensor to ethanol, acetone, formaldehyde, and ammonia are greatly higher than those of the nanorod/the nanocube sensors. The nanotubes showed enhancing gas-sensitive properties. The responses of the nanotube sensor reached 75, 26, 6.8, 1.7 to 200 ppm acetone, ethanol, formaldehyde, and ammonia at 270 degrees C and a 30-45% relative humidity, respectively, which shows high selectivity. So the nanotubes are gas-sensing materials more excellent than nanorods and nanocubes.

A novel structure for enhancing the sensitivity of gas sensors – α-Fe2O3 nanoropes containing a large amount of grain boundaries and their excellent ethanol sensing performance

“…43 These results provide further evidence that the unique structure of a-Fe 2 O 3 nanoropes could effectively enhance the sensor device sensitivity. 43 These results provide further evidence that the unique structure of a-Fe 2 O 3 nanoropes could effectively enhance the sensor device sensitivity.…”

“…Obviously, the a-Fe 2 O 3 nanoropes have higher sensitivity than single crystalline a-Fe 2 O 3 nanorods. 43 These results provide further evidence that the unique structure of a-Fe 2 O 3 nanoropes could effectively enhance the sensor device sensitivity. Taking the measuring temperatures and recovery time into account, it is reasonable to say that the a-Fe 2 O 3 nanoropes prepared in this work is of high quality.…”

On the Use of Pulsed UV or Visible Light Activated Gas Sensing of Reducing and Oxidising Species with WO3 and WS2 Nanomaterials

“…Some different operating principles such as electrochemical [ 5 , 6 ], optical [ 7 , 8 ], or chemiresistive have been used for gas sensing [ 9 , 10 , 11 , 12 ] related to air quality monitoring. One of the most studied approaches has been the use of metal oxides (MOX) chemiresistors due to their high sensitivity and the relatively simple associated driving and readout electronics, which confers them enormous versatility for being employed in a wide range of different applications, such as toxic and combustible gas detection, biosensing, environmental safety, and food quality control [ 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 ].…”

Highly selective and sensitive response of Polypyrrole–MnO2 based composites towards ammonia gas

“…Gas sensors based on metal oxides such as CuO, In 2 O 3 , TiO 3 , Fe 2 O 3 , and ZnO have been practiced [6][7][8][9][10]. These sensors have good performance with respect to sensitivity, response and recovery time.…”