Abstract
This study compared the responses of Pd-functionalized and pristine titanate (TiO2) nanotube arrays to ethanol with those to acetone to determine the effects of functionalization of TiO2 nanotubes with Pd nanoparticles on the sensitivity and selectivity. The responses of pristine and Pd-functionalized TiO2 nanotube arrays to ethanol gas at 200 °C were ∼2877% and ∼21,253%, respectively. On the other hand, the responses of pristine and Pd-functionalized TiO2 nanotube arrays to acetone gas at 250 °C were ∼1636% and 8746% respectively. In the case of ethanol sensing, the response and recovery times of Pd-functionalized TiO2 nanotubes (10.2 and 7.1 s) were obviously shorter than those of pristine TiO2 nanotubes (14.3 and 8.8 s), respectively. In contrast, in the case of acetone sensing the response and recovery times of Pd-functionalized TiO2 nanotubes (42.5 and 19.7 s) were almost the same as those of pristine TiO2 nanotubes (47.2 and 17.9 s). TiO2 nanotube arrays showed the strongest response to ethanol and Pd functionalization was the most effective in improving the response of TiO2 nanotubes to ethanol among six different types of gases: ethanol, acetone, CO, H2, NH3 and NO2. The origin of the superior sensing properties of Pd-functionalized TiO2 nanotubes toward ethanol to acetone is also discussed.
Highlights
Titanate (TiO2) is one of the most widely studied semiconductor materials
The sensing properties of pristine and Pd-functionalized TiO2 nanotube array sensors toward ethanol and acetone were compared to determine the effects of the metal catalyst on the sensitivity and selectivity of the sensors
With increasing calcination temperature, TiO2 crystallizes into two phases: rutile and anatase with anatase dominant at lower temperatures
Summary
Titanate (TiO2) is one of the most widely studied semiconductor materials. Formation of TiO2 nanotubes was reported for the first time by Hoyer [1]. The functionalization of semiconductor gas sensors with metal catalysts is one of the most commonly used techniques for enhancing the sensitivity of gas sensors. Four kinds of metal catalyst-functionalized TiO2 nanotube arrays were assessed to detect a range of gases, but their sensing properties toward ethanol gas were not reported. The mechanism through which the sensitivity of a gas sensor is enhanced by functionalizing the sensor material with metal catalysts is well established [28,29,30,31]. The sensing properties of pristine and Pd-functionalized TiO2 nanotube array sensors toward ethanol and acetone were compared to determine the effects of the metal catalyst on the sensitivity and selectivity of the sensors. Pd has been most commonly adopted as a metal catalyst because of its excellent catalytic behavior
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
