ABSTRACT
Greenhouse gas emission mostly accounts for global warming effect, hence the urgency to realize $\text{CO}_{2}$ removal efficiently and harmlessly to the environment. Base on all of these requirements, utilization of abundant solar energy to achieve $\text{CO}_{2}$ reduction seems the be the best choice. In this review, mechanisms of $\text{CO}_{2}$ photoreduction is briefly introduced, including electrochemical potential analysis and chemical reaction mechanism. Efficiency measurements in this filed are summarized, mainly divided into two groups: catalyst-based measurement and light-based measurement. Applications of $\text{TiO}_{2}$ on $\text{CO}_{2}$ reduction will follow. Subsequently, the modifications on $\text{TiO}_{2}$ specifically for its efficiency and selectivity are discussed in details.