【摘要】：近年來(lái),隨著科學(xué)技術(shù)的快速發(fā)展,環(huán)境污染問(wèn)題越來(lái)越嚴(yán)重。周圍環(huán)境中可能存在著各種有毒有害易燃易爆氣體,其潛在的影響著人們的日常生活和生產(chǎn)活動(dòng),因此,如何及時(shí)監(jiān)測(cè)這些危害性氣體引起人們高度的重視。苯類化合物作為重要的有機(jī)溶劑廣泛應(yīng)用于多種家居用品和工業(yè)產(chǎn)品,所以苯類氣體污染普遍存在于住宅區(qū)及工業(yè)環(huán)境中。由于苯類氣體的劇毒性和致癌性,長(zhǎng)時(shí)間處于低濃度的環(huán)境氣氛也會(huì)對(duì)身體健康造成極大的傷害,所以檢測(cè)低濃度的苯類氣體是一項(xiàng)重要的任務(wù)。目前為止,多種半導(dǎo)體金屬氧化物氣體傳感器已應(yīng)用于苯類氣體檢測(cè),然而苯類分子具有高的反應(yīng)活化能和化學(xué)穩(wěn)定性,使其檢測(cè)難度大大增加,所以現(xiàn)有的苯類半導(dǎo)體氣體傳感器都存在著一些缺陷,例如靈敏度低,工作溫度高,檢測(cè)限高,響應(yīng)-恢復(fù)時(shí)間長(zhǎng)等。ZnO是一種典型的半導(dǎo)體金屬氧化物敏感材料,已有很多關(guān)于其檢測(cè)苯類氣體的研究,但是這些研究方法同樣存在著上述的問(wèn)題,為了解決這些檢測(cè)難點(diǎn)我們對(duì)ZnO材料進(jìn)行了改性研究,通過(guò)修飾具有催化活性的貴金屬提高ZnO半導(dǎo)體材料對(duì)苯類氣體的傳感性能。(1)選用貴金屬Au作為修飾劑,通過(guò)溫和的溶劑熱和簡(jiǎn)單的熱處理方法制備多孔Au/ZnO復(fù)合材料,該復(fù)合材料對(duì)苯類氣體表現(xiàn)出優(yōu)異的氣敏性能。其中1 wt.%Au/ZnO復(fù)合材料對(duì)100 ppm苯的響應(yīng)值最高且達(dá)到60,是純ZnO響應(yīng)值的5倍。另外,1wt.%Au/ZnO傳感器具有低的檢測(cè)限(0.5ppm),低的工作溫度(260℃),快速的響應(yīng)-恢復(fù)時(shí)間,長(zhǎng)期的循環(huán)穩(wěn)定性,并且苯濃度與響應(yīng)值的對(duì)數(shù)呈現(xiàn)很好的線性關(guān)系。分析認(rèn)為Au/ZnO復(fù)合材料苯敏性能的提高主要源于Au的催化作用和肖特基勢(shì)壘。(2)通過(guò)上述的制備方法獲得痕量Pt負(fù)載的ZnO復(fù)合材料,氣敏測(cè)試發(fā)現(xiàn)Pt負(fù)載也可大幅度提高ZnO材料對(duì)苯、甲苯、二甲苯氣體的氣敏性能。系統(tǒng)研究得出基于0.1 wt%Pt-ZnO的氣體傳感器表現(xiàn)出最佳的氣敏性能,在250℃的工作溫度下對(duì)100 ppm苯的響應(yīng)值能達(dá)到70。值得一提的是,其能快速的檢測(cè)出100 ppb苯,達(dá)到室內(nèi)苯類污染物的安全檢測(cè)標(biāo)準(zhǔn)。Pt-ZnO復(fù)合材料對(duì)苯類氣體杰出的響應(yīng)特性歸因于貴金屬Pt的催化活性,肖特基勢(shì)壘和p-n異質(zhì)結(jié)的電子效應(yīng)。
[Abstract]:In recent years, with the rapid development of science and technology, environmental pollution is becoming more and more serious. There may be a variety of toxic, harmful, flammable and explosive gases in the surrounding environment, which have a potential impact on people's daily life and production activities. Therefore, how to monitor these harmful gases in time has attracted great attention. Benzene compounds as important organic solvents are widely used in a variety of household products and industrial products, so benzene gas pollution generally exists in residential areas and industrial environment. Because of the high toxicity and carcinogenicity of benzene gas, it is an important task to detect benzene gas in low concentration environment for a long time. Up to now, many kinds of semiconductor metal oxide gas sensors have been applied to the detection of benzene gases. However, benzene molecules have high reaction activation energy and chemical stability, which greatly increase the difficulty of their detection. Therefore, the existing benzene semiconductor gas sensors have some defects, such as low sensitivity, high operating temperature, high detection limit, long response-recovery time, etc. ZnO is a typical semiconductor metal oxide sensitive material. There have been many studies on the detection of benzene gases, but these research methods also have the above problems. In order to solve these difficulties, we have studied the modification of ZnO materials. The sensing properties of ZnO semiconductor materials to benzene gases were improved by modifying the noble metals with catalytic activity. (1) the porous Au/ZnO composites were prepared by mild solvothermal and simple heat treatment with noble metal Au as modifier. The composite exhibits excellent gas sensitivity to benzene gases. The response value of 1 wt.%Au/ZnO composite to 100 ppm benzene was the highest and reached 60, which was 5 times of that of pure ZnO. In addition, 1wt.%Au/ZnO sensors have low detection limit (0.5ppm), low operating temperature (260 鈩，

本文編號(hào)：2391048