张全, 陈雪梅, 叶盛英, 李利钦, 崔晓雷, 王熠. 辐照改性银掺杂TiO2纳米管催化紫外光降解乙烯效果[J]. 农业工程学报, 2016, 32(23): 278-283. DOI: 10.11975/j.issn.1002-6819.2016.23.038
    引用本文: 张全, 陈雪梅, 叶盛英, 李利钦, 崔晓雷, 王熠. 辐照改性银掺杂TiO2纳米管催化紫外光降解乙烯效果[J]. 农业工程学报, 2016, 32(23): 278-283. DOI: 10.11975/j.issn.1002-6819.2016.23.038
    Zhang Quan, Chen Xuemei, Ye Shengying, Li Liqin, Cui Xiaolei, Wang Yi. Photocatalytic degradation of ethylene using titanium dioxide nanotube arrays with Ag doped and irradiated by γ-ray radiolysis[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2016, 32(23): 278-283. DOI: 10.11975/j.issn.1002-6819.2016.23.038
    Citation: Zhang Quan, Chen Xuemei, Ye Shengying, Li Liqin, Cui Xiaolei, Wang Yi. Photocatalytic degradation of ethylene using titanium dioxide nanotube arrays with Ag doped and irradiated by γ-ray radiolysis[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2016, 32(23): 278-283. DOI: 10.11975/j.issn.1002-6819.2016.23.038

    辐照改性银掺杂TiO2纳米管催化紫外光降解乙烯效果

    Photocatalytic degradation of ethylene using titanium dioxide nanotube arrays with Ag doped and irradiated by γ-ray radiolysis

    • 摘要: 为了解辐照改性银掺杂二氧化钛纳米管阵列(titanium dioxide nanotube arrays,TNTAs)半导体材料对光催化降解冷藏环境中乙烯的影响,该文首先通过阳极氧化法制备TNTAs,后用60Co-γ射线对TNTAs进行辐照改性,再用辐照还原技术制备纳米银颗粒,最后用纳米银掺杂制备TNTAs-Ag光催化材料。利用场发射扫描电镜(field emission scanning electron microscope)、X-射线衍射(X-ray diffraction)、X-射线光电子能谱(X-ray photoelectron spectroscopy)对半导体材料表征,结果表明:辐照能把无定型TNTAs转化为锐钛矿晶型,随辐照剂量提高,锐钛矿晶型衍射峰越来越尖锐,晶粒尺寸渐趋减小;TNTAs表面掺银后,银粒子以团簇形式沉积于TNTAs管口处,并未进入管壁内部。在模拟园艺产品冷藏环境中,进行紫外光催化降解乙烯研究,结果表明:辐照剂量为20 kGy时,降解效果达最优,速率常数K′为2.03×10?4 min?1;纳米Ag引入后,TNTAs-Ag速率常数K′可达5.88×10?4 min?1,与未掺杂仅辐照的TNTAs相比提高了189.66%。

       

      Abstract: Abstract: Fruits and vegetables can produce large amounts of ethylene when stored in an enclosed storage space after harvest, which can accelerate the maturity and aging of fruits and vegetables. Due to the existence of ethylene in closed storage environment and inappropriate storage methods, a large amount of horticultural products is deteriorated, resulting in huge economic losses every year. Because of large surface area, stable chemical property, excellent charge transport characteristic and available recycling properties, TiO2 nanotube arrays (TNTAs) have been used widely in sensors, dye-sensitized solar cells, light catalytic cracking water into hydrogen, degradation of organic pollutants and other related fields. Even though the formation of TNTAs are highly ordered and vertical growth on titanium substrate, the recombination of photo-generated electrons and hole pairs at the surface of TNTAs is an issue, which seriously limits the catalytic efficiency for ethylene degradation. In order to study the influence of semiconductor materials of titanium dioxide nanotube arrays modified with Ag-doped and 60Co γ-ray irradiation on photocatalytic degradation of ethylene in cold storage environment, we prepared TNTAs with anodic oxidation method followed with60Co γ-ray irradiated on it for modification. Anodic oxidation method can be used to prepare titanium dioxide nanotube arrays with different dimensions conveniently through controlling anode potential, electrolyte concentration, and temperature, which have been considered as one of the most popular ways for enhancing the photocatalytic efficiency of TiO2. Gamma rays have been observed to play a key role in inducing disruption and dislodgement of electrons and sometimes atoms within a crystal to create defects in the crystal structure. After the formation of TNTAs, silver nanoparticles were made by irradiated reduction technology and doped on TNTAs to make up the new photocatalytic material of TNTAs-Ag. The addition of Ag nanoparticles can make photo-generated electrons transfer from a higher energy level of TiO2 to the noble metal with a lower Fermi level so that the electrons and holes can be separated rapidly.Field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) were used to analyze the characterization of the prepared semiconductor materials. Results showed that: irradiated modification can transfer amorphous crystal of TNTAs to anatase crystal. The diffraction peak of anatase crystal becomes more and more sharp and the crystal dimension becomes smaller and smaller with the increase of irradiation dose, indicating that silver particles adhered to the nozzle of TNTAs in the form of cluster deposition and it didn't not enter internal wall after doping the surface of TNTAs. Experiments of photocatalytic degradation of ethylene with TNTAs and TNTAs-Ag under ultraviolet in simulating cold storage environment were also conducted, where rate constant K′ was chosen to represent the degradation ability of ethylene. It turned out that: optimal rate constant K′ can reach up to 2.03×10-4 min-1 when TNTAs were irradiated under 20 kGy. After modifying Ag on irradiated TNTAs, the rate constant K′ increased by 189.66% compared with irradiated modification separately, the constant was 5.88×10-4 min-1.

       

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