During the last century, human activity has increased the amount of greenhouse gases in the atmosphere, especially the excessive emission of carbon dioxide from burning fossil fuels. In the last 50 years, carbon emissions have increased tenfold and are currently still rising. The CO2 concentration in the Earth’s atmosphere has risen from 270 ppm to > 400 ppm; Artificial CO2 (photo-chemical) recycling through solar energy plays an essential role in removing CO2 from the atmosphere and provides a new energy source simultaneously through efficient CO2 reduction. In this research proposal, mechanisms of photocatalytic and photoelectrochemical CO2 reduction, the critical factors on designing photocatalysts, and the photoelectrochemical reactor will be discussed. The proposal for the design of full solar spectrum photocatalysts will be presented, followed by preliminary studies of my research work in this field. ​