Effect of thermal treatment temperature on catalytic performance of Pt/TiO2 nanobelt composite for HCHO oxidation
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摘要: 采用水热合成法并结合酸处理制备出TiO2纳米带,进行不同温度热处理,在TiO2纳米带上沉积Pt纳米颗粒(NPs),制备出一系列Pt/TiO2纳米带复合物,用于甲醛室温催化氧化。通过各种技术对催化剂进行表征,结果表明,热处理温度对TiO2纳米带的相组成和表面结构,以及表面的氧空位和羟基的数量有较大的影响。在室温下,600 ℃热处理的TiO2纳米带负载Pt催化剂具有更为丰富的氧空位,有利于吸附氧的活化,并形成较多的Ti-(OH)x-Pt物种,表现出较高的催化活性,在25 ℃,相对湿度为55%时,甲醛的转化率为91.6%。Abstract: TiO2 nanobelts were prepared by hydrothermal synthesis and acid treatment, then calcination at different temperatures. And subsequently Pt nanoparticles were deposited on the TiO2 nanobelts. Pt/TiO2 catalytic properties were investigated in the oxidation of formaldehyde. These catalysts were characterized by various techniques and the characterization results showed that the applied thermal treatment temperature greatly influenced the phase composition and surface structure of TiO2 nanobelts, as well as the number of oxygen vacancies and hydroxyl groups on the surface. The Pt/TiO2 nanobelts thermally treated at 600 °C had more oxygen vacancies, which were conducive to the activation of adsorbed oxygen, formed more Ti-(OH)x-Pt species, and showed higher catalytic activity. At 25 °C and relative humidity of 55%, the conversion of formaldehyde reached 91.6%.
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Key words:
- formaldehyde /
- phase structure /
- thermal treatment temperature /
- oxygen vacancies /
- catalytic oxidation
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表 1 Pt/TiO2催化剂的物化性质和Pt金属分散度
Table 1 Physical properties and Pt dispersion of the Pt/TiO2 catalyst
Pt/TiO2
catalystABET/
(m2·g−1)Pore volume /
(m3·g−1)Pore size /
nmPt
dispersion/%PT-C200 81 0.22 8.9 42.2 PT-C300 77 0.22 9.3 40.4 PT-C400 70 0.21 9.7 38.2 PT-C500 64 0.18 11.2 37.2 PT-C600 56 0.16 12.0 37.1 PT-C700 51 0.15 12.5 34.3 表 2 PT-C300和PT-C600催化剂的XPS分析
Table 2 XPS analysis results for the catalysts of PT-C300 and PT-C600
Catalyst BE (eV) Surface atom ratio Pt 4f7/2(Pt 4f5/2) OII (OI) Ti 2p OII /(OI+ OII) Pt/Ti Pt2+/Pt0 PT-C300 70.90(74.10) 531.80(529.75) 458.75 0.462 0.041 0.767 PT-C600 70.60(74.00) 531.85(529.80) 458.35 0.618 0.036 0.361 OⅡ/(OⅠ+ OⅡ) and Pt2+/Pt0 were calculated from the corresponding areas of fitted peaks done by XPSPEAK 4.1 with Shirley background -
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