关键词: 二氧化碳, 光化学, 还原, 能带, 半导体

Abstract: In the process of photocatalytic reduction of CO2，visible light could be absorbed perfectly by the catalyst with a narrowed band gap，but those absorbed light could not be entirely devoted to photocatalytic reduction of CO2，as photocatalytic reduction performance is directly related to energy band location and band structure changing has an important influence on redox ability. Beginning with the CO2 photocatalytic reduction basic principles，this paper is aimed to introduce the basic reduction process of CO2 by semiconductor photocatalyst，the decisive role of valence band and conduction band；to briefly discuss the existing mismatch problem of valence band and conduction band in the process of photocatalytic reduction of CO2；and also to describe how to improve the CO2 photocatalytic reduction efficiency using energy band match theory，such as crystal growth，composite materials，form “p-n junction” and the First Principles，which provides theoretical references for the selection and design of catalyst for the photocatalytic reduction of CO2.

Key words: carbon dioxide, photochemistry, reduction, energy band gap, semiconductor