光电催化转化是实现二氧化碳合理化、高效化利用的重要途径之一。但是，光电极材料催化效率低和稳定性较差严重制约了该领域的发展。因此，开发性能稳定、效果优良、清洁廉价的光电极材料是目前研究的重要方向。本论文主要探讨了TiO2@g-C3N4@CoPi复合光阳极和Cu2O@ZnO光阴极催化材料的制备方法，并对两种光电极催化剂的结构和性能进行了表征。以提高有效电荷利用率为目的，设计了双池二氧化碳光电催化还原体系，在该体系上评价了两种光电极的二氧化碳光电还原制甲醇的催化活性。研究结果对于光电极催化剂的制备与应用有一定的理论意义。主要研究结果如下： (1) 采用水热合成、化学浴及电化学沉积等方法，制备了TiO2@g-C3N4@CoPi光阳极复合材料。通过控制水热过程中钛酸丁酯的用量，调节TiO2纳米棒的疏密程度；通过改变化学浴溶液中尿素的用量，调节g-C3N4在TiO2上的负载量；通过调节电渡时间，控制CoPi在TiO2@g-C3N4上负载量。结果表明，当g-C3N4在TiO2上的负载量为10%，电镀时间为30 min时，TiO2@g-C3N4@CoPi光阳极材料展现出最佳光电性能；在100 mW/cm2 (AM 1.5G)的光照下，施加1.23 V(vs. RHE)的偏压，该材料的LSV电流密度达到1.6 mA/cm2。经过10 h的稳定性测试后性能几乎没有出现衰减。 (2) 采用水热法和化学浴法制备了Cu2O@ZnO光阴极复合材料。选取导电性好的Cu片作为电极基底，通过化学浴法在基底上生长球状Cu2O颗粒。运用水热法在Cu2O颗粒表面进一步生长ZnO纳米分支，以构成异质结，并增加电极的比表面积。结果表明，利用Cu2O@ZnO光阴极进行二氧化碳的光电催化还原实验时，在-1.1 V (vs. RHE)的偏压下，还原二氧化碳得到甲醇的法拉第效率达到最大值7.9%。 (3) 以提高有效电荷利用率为目的，设计了双池二氧化碳光电催化还原体系。采用已经制备得到的复合n型半导体TiO2@g-C3N4@CoPi作为光阳极，复合p型半导体Cu2O/ZnO作为光阴极，分别放置于两个反应室中，中间由盐桥连接，在光照以及偏压的作用下进行二氧化碳的光电催化还原。该催化体系在-1.0 V (vs. RHE)的偏压下，还原二氧化碳得到甲醇的法拉第效率达到最大值9.6%。

The photocatalytic conversion of carbon dioxide to valuable chemicals is not only an effective way to solve the greenhouse effect, but also a clean way to ensure rational use of carbon resources. However, poor efficiency and stability of catalyst limit the blossom of this technic. So the research and development of catalyst with stable performance and high efficiency is needed. TiO2@g-C3N4@CoPi photoanode and Cu2O@ZnO photocathode were used to assemble the carbon dioxide catalytic reduction system. The oxidation of water and reduction of carbon dioxide was divided into two reaction chamber. So that carbon dioxide can be efficiently reduced by clean solar energy. This study not only can provide new ideas for clean and efficient conversion of carbon dioxide, but also has important significance for the preparation and application of other photoelectrode in this field. The research results are as follows: (1) TiO2@g-C3N4@CoPi photoanode was prepared by three processes of hydrothermal method, chemical bath and electrochemical deposition. First of all, the density of titanium dioxide nanorod was adjusted by controlling the concentration of tetrabutyl titanate precursor. Second, the g-C3N4 quantity deposited on the surface of TiO2 was optimized through various concentration of urea in the chemical bath solution. Finally, after 30 min electrochemical deposition, we get the final product TiO2@g-C3N4@CoPi photoanode composite material. The results indicated that the LSV photocurrent density of TiO2@g-C3N4@CoPi reaches up to 1.6 mA/cm2, which is 3.8-fold that of TiO2 nanorod arrays (TiO2 NRs) (0.42 mA/cm2) at bias 1.23 V (vs. RHE). The photocurrent density of TiO2@g-C3N4@CoPi was quite stable and more than 90% of the initial photocurrent density was still sustained after continuous 10 h illumination at bias potentials 1.23 V (vs. RHE). (2) Cu2O@ZnO composite photocathode was prepared via a facile hydrothermal growth and chemical bath process. Firstly, the spherical Cu2O particles were grown at Cu substrate with good conductivity by chemical bath. Secondly, ZnO nanobranch was deposited at the surface of Cu2O particles by hydrothermal growth. This kind of composite structure not only can constitute heterojunction to improve the efficiency of charge separation, but also can greatly accelerate the charge transfer by increasing the surface area. The faradic efficiency of Cu2O@ZnO as photocathode can reach up to the maximum value 7.9%, at the bias of -1.1 V (vs. SCE). (3) Under the inspiration of proton exchange membrane fuel cell, we designed a novel phtotoelectrochemical cell with two compartments connected by salt bridge for carbon dioxide reduction. This system was consisted of the prepared n-type semiconductor photoanode TiO2@g-C3N4@CoPi and p-type semiconductor photocathode Cu2O/ZnO. Employing the novel system, the reaction of carbon dioxide reduction and water oxidation occurred at the same time in the cathode part and anode part, respectively. Under the bias of -1.0 V (vs. SCE), the faradic efficiency of CO2 reduction system could get maximum 9.6%.