【作者】 洪益娟；

【导师】 张钦辉；

【作者基本信息】 华东理工大学 ， 化学工程， 2011， 硕士

【摘要】 作为最重要的温室效应气体之一,CO2由于其稳定的化学性质,采用传统方式进行转化时存在条件苛刻能耗过高等问题。以TiO2为催化剂的光催化方法可以使得C02在较温和的条件下得到转化,并且以太阳光作为能量来源绿色环保,不会造成二次污染。基于以上考虑,本文尝试采用TiO2为催化剂对光催化水蒸气还原二氧化碳制备含碳有机物的反应进行了一系列的研究,并对催化剂进行改性,以期更好的催化效果通过溶胶凝胶法合成了锐钛矿型TiO2,以商品TiO2(P25)和自制TiO2为载体,采用浸渍法制备了不同CuO含量的CuO/TiO2纳米颗粒光催化剂；采用XPS、XRD、XRF、HRTEM、PL和BET等方法对催化剂样品的组成结构进行了一系列的分析表征；在自建的气固相光催化反应体系中对光催化H2O还原CO2反应进行了一系列考察,对催化剂的光催化性能进行评价；通过对产物的定性和定量分析考察了催化剂铺展方式、CuO含量、反应温度、光辐射时间、反应原料水碳比等因素对光催化反应的影响,探索了催化剂物化性质与光催化性能之间的内在关系。研究结果表明,在紫外光照射条件下,CuO/TiO2纳米光催化剂能够在温和条件下(常压和较低温度)用水蒸气为还原剂将CO2还原成CH4、C2H4和C2H6等含碳化合物；通过CuO的负载可有效提高TiO2的紫外光响应强度,从而提高催化活性。通过对CuO/TiO2纳米颗粒催化剂的研究,混合晶相的商品TiO2系列催化剂活性明显优于溶胶凝胶法自制TiO2系列催化剂活性,并且CuO具有最佳负载量1.5wt.%,333 K条件下,水碳比0.02,紫外光照射17h,主产物CH4生成量为6.375μmol·g·cat-1;提高水碳比、反应温度、紫外辐射强度等条件,采用涂膜方式铺展催化剂,均能有效提高CH4等产物的累积生成量。更多还原

【Abstract】 CO2, as one of the important main greenhouse gases, is chemically stable, so the conversion of CO2 in conventional methods leads to several troubles such as high enegy-consuming and strict condition. The photocatalytic reaction can converts CO2 into more useful compounds such as methane, methanol,. and formaldehyde. In addition, by harnessing solar energy the photocatalytic process is less energy-consuming than the conventional methods. Therefore, the photocatalytic conversion of CO2 with water vaper in the presence of TiO2 has been studied in this paper and the photocatalyst has been modified for better activity.Nano-anatase-TiO2 particle has been synthesized via sol-gel methods. Different CuO content supported/composite photocatalysts were synthesized via impregnation methods. The composition and structure property of these photocatalysts were characterized by XPS, XRD, HRTEM, PL, BET and XRF. The photocatalytic conversion reaction of CO2 was examined in a self-designed fixed-bed photocatalytic reactor. The influence of different kind of CuO/TiO2, reaction temperature, H2O/CO2 ratio of the raw material and irradiation intensity were systematically studied in the photocatalytic reduction of CO2 with H2O.Methane (CH4), carbon monoxide(CO), ethene(C2H4) and trace amout of ethane has been found in the reactor as the prouduct of photocatalytic reduction of CO2 in contact with water using CuO/TiO2 catalysts under the UV irradiation at mild conditions of low pressure and temperature. The photocatalytic activity could be significantly improved with appropriate CuO content and the optimal content of CuO was 1.5 w.% in CuO/TiO2 nano particle catalysts which was prepared by P25, CH4 yield reached 6.375μmol·g·cat-1 after 17 h irradiation at 333 K with H2O/CO2=0.02. Meanwhile, the catalysts synthesized via sol-gel methods show lower reactivity than others. The CH4 yield can be enhanced by increasing the reaction temperature, H2O/CO2 ratio and UV irradiation duration. By using the coating treatment on the catalyst during the experimentation, efficiency of the reaction has been improved.更多还原