奈米(鉑,金)附載奈米氧化錫感測器之製備與CO氣體感測效能評估

Preparation and CO Gas-Sensing Performance Evaluation of Pt/SnO2 and Au/SnO2 nanoparticle Gas Sensors

陳鈺凱(Yu-Kai Chen)

指導教授 ： 張幼珍

元智大學/工程學院/化學工程與材料科學學系/碩士(2008年)

https://doi.org/10.6838/YZU.2008.00298

摘要

本研究主要分成兩部分。其一是以扁平焰合成之奈米氧化錫粉體之樣品製備與特性分析，實驗參數包括燃氣比、反應腔體壓力、合成時間等。XRD結果顯示燃氣比為氧氣過量時可獲致晶粒平均粒徑在18-33nm範圍間、四方晶形（tetragonal），或金紅石結構（rutile structure）的氧化錫粉體，晶粒大小隨反應腔體壓力上升而上升；TEM結果顯示粉體形貌為實驗參數的函數，合成時間越短，粉體粒徑與形貌越趨均勻的球形，合成時間越長，粉體粒徑與形貌越趨不均勻，推測粉體合成後繼續受到來自火焰的輻射熱而在沉積基材上繼續固相燒結所造成。
計畫第二部份工作為製作奈米氧化錫感測器與其CO氣體感測效能評估。研究中評估包括火焰直接合成的氧化錫感測器、燒結後的氧化錫感測器、利用氣相濺鍍將Pt奈米觸媒沉積於前兩種氧化錫奈米粉體的感測器、與氣相濺鍍將Au奈米觸媒沉積於前兩種氧化錫奈米粉體的感測器。感測器性能測試結果顯示六種感測器的導電度均隨CO濃度的上升而呈現線性上升的趨勢，奈米氧化錫微粒粒徑會隨感測器感測溫度而改變，導致感測反應表面積在量測過程中的變化，研究中發現將氧化錫做適當燒結處理後可得到高穩定性且具重複性的感測訊號。

關鍵字

奈米氧化錫、氣體感測器、一氧化碳、低壓扁平焰、奈米金、奈米鉑

並列摘要

The objectives of this study are two-fold: (1) the preparation of tin oxide (SnO2) nanoparticles and (2) the preparation of prototype SnO2-based sensors. The first part is involved with the preparation and characterization of SnO2 nanoparticles. Experimental parameters include fuel/gas ratio, pressure of reaction chamber, and synthesis time. XRD results suggest rutile phase SnO2 nanoparticles in 18-33nm range can be produced under oxygen excess condition. It was also found that the grain size increases with increasing chamber pressure. TEM result shows particle morphology is a function of all three parameters. A shorter synthesis time yields more spherical and uniformly-sized tin oxide nanoparticles, while a longer synthesis time leads to non-uniformly-sized nanoparticles in a wide variety of shapes, possibly due to extensive radiative heating of the flame over the deposited nanoparticle layer.
The second part of this study is involved with the preparation of prototype nano- SnO2 gas sensors using the flame derived tin oxide nanoparticles and their sensing performance towards carbon monoxide gas (mixed with air) in 100-500ppm range. Six types of sensors were prepared. They are: sensor prepared with SnO2 (as-derived), SnO2 (sintered), nano-Pt sputtered on SnO2 (as-derived), nano-Pt sputtered on SnO2 (sintered), nano-Au sputtered on SnO2 (as-derived), and nano-Au sputtered on SnO2 (sintered). Preliminary results showed particle size is subject to change under the sensing temperature used in this study, which leads to unstable and non-linear sensor response. After proper post-heat treatment of the flame-derived SnO2 particles and pre-conditioning the sensor modules, all sensors exhibited a repeatable, linear relationship between sensor conductance and CO concentration.

並列關鍵字

tin oxide nanoparticle, gas sensor, carbon monoxide, low-pressure flat flame, nano-gold, nano-platinum

參考文獻

44. Ganhua Lu, Kyle L. Huebner. Leonidas E.Ocola, Marija Gajdardziska-Josifovska, and Junjong Chen (2006). "Gas Sensor Based on Tin Oxide Nanoparticles Synthesized Form a Mini-Arc Plasma Source".

2. Glumac, N.G. and D.G. Goodwin, "Diagnostics and Modeling of Strained Fuel-Rich Acetylene / Oxygen Flames Used for Diamond Deposition," Combustion and Flame, 105, 321 – 331, 1996.

3. Glumac, N.G.; Goodwin, D.G.; “Large-area diamond film growth in a low-pressure flame,” Materials Letters, 18(3), 119-122, 1993.

5. Ho, C.K., A. Robinson, D.R. Miller and M.J. Davis, “Overview of Sensors and Needs for Environmental Monitoring,” Sensors, 5, 4-37, 2005.

6. Skandan, G.; Chen, Y.J.; Glumac, N.; Kear, B.H., “Synthesis of oxide nanoparticles in low pressure flame,” Nano Stuctured Materials,” 11, NO.2, 149-158, 1999.