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清洁的多晶金属钛表面碱性强,甲醇、甲酸和甲醛在该表面上均呈分解吸附,表面产生碳化钛、氧化钛、OH、CH_x、和CH_xO(x≤3)等物种,在甲酸吸附时还可观察到HCOO的存在。TiO_2(100)完整表面碱性较弱,在甲醇的吸附反应中,表面只观察到OH、CH_x和CH_xO,甲醛室温在该表面吸附也产生类似物种,加热至700K,表面形成了HCOO。在TiO_2(100)氧缺位表面,室温时甲醇和甲醛的吸附量大于其完整表面,这表明氧缺位表面有较强的碱性,甲醛在其表面吸附并加热至700K,表面并没有HCOO产生;甲酸在其表面吸附,主要产物为CH_xO,HCOO浓度十分低。可见TiO_2(100)氧缺位表面具有切断C-O键的能力,而TiO_2(100)完整表面则具有将HCO氧化为HCOO的能力。
The surface of the clean polycrystalline titanium has strong alkalinity. Methanol, formic acid and formaldehyde are decomposed and adsorbed on the surface. Titanium carbide, titanium oxide, OH, CHx, and CHxO (x? 3) The presence of HCOO can also be observed. In the methanol adsorption reaction, only OH, CH_x and CH_xO were observed on the surface of TiO_2 (100). Similar adsorption was also observed on the surface of TiO_2 (100). When heated to 700K, HCOO was formed on the surface. The adsorption of methanol and formaldehyde on TiO 2 (100) vacancy surface was larger than that on intact surface at room temperature, which indicated that the oxygen vacancy surface had strong basicity. Formaldehyde was adsorbed on the surface and heated to 700K without HCOO Generated; formic acid adsorbed on its surface, the main product is CH_xO, HCOO concentration is very low. It can be seen that the oxygen vacancy surface of TiO 2 (100) has the ability to cut C-O bonds, whereas the complete surface of TiO 2 (100) has the ability to oxidize HCO to HCOO.