Titania was modified by macrocyclic complexes applying a new method of in-situ sol-gel. Cobalt phthalocyanine (CoPc) is synthesized in the processing of TiO2 gel synthesis and obtained the nano-cata-lyst of 10. 89 nm CoPc/TiO2. This catalyst was applied to photocatalytic reduce CO2, exposure under visible light, in the water solution. CO2 Can be reduced to HCHO, CH30H, HCOOH and so on. Results showed that because of the CoPc, the particle size and the temperature of phase transformation is reduced. CoPc was isolated homogeneously in the pores of the titania matrix. The dimerization and aggregation of CoPc molecules is decreased and it is favored to transfer electrons from excited CoPc to the conduction band of TiO2. The photo-efficiency is greatly increased. The optimum reaction conditions of photocatalytic reduction CO2 were as follows: concentration of NaOH 0. 1 mol/L,catalyst of CoPc/TiO2 0.15 g. The efficiency of reaction is good if TEA and TEOA were sacrificial electron donors. After 10 h of photo-reaction, the TOC can reach 2 965. 3 μmol/g-cat. In the process of CO2 reduction, the HCO3 - was the main ion but nor CO3 2-. The optimum concentration of HCO3- was 0. 2 mol/L, the reduction products were the largest.%采用原位溶胶-凝胶法合成氧化钛,同时对大环配合物进行改性,得到粒径为10.89 nm的纳米级钴酞菁改性氧化钛( CoPc/TiO2)光催化剂,用于可见光下、水溶液中CO2的还原反应,可得HCHO、CH3 OH、HCOOH等产物.结果表明,由于金属酞菁的存在导致TiO2粒径减小,相转变温度降低,CoPc以单体形式均匀分散于TiO2凝胶基质中,其二聚及多聚倾向大大减弱.钴酞菁固载的催化剂给电子能力较强,极大地提高了光还原效率.光反应的最佳条件为:在0.1 mol/L的NaOH溶液中,0.15 g CoPc/TiO2催化剂,三乙胺和三乙醇胺作为电子供体催化效果较好,在可见光照反应10h后,还原产物中总有机碳最高可达2 965.3 μmol/g-cat.在还原过程中CO2主要以HCO3 -的形式被还原而非碳酸根离子,而且HCO3 -的浓度在0.2 mol/L时还原产物量最大.
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