Conventional sources of renewable energy cannot yet accommodate large-scale generation of transportation fuel. One of the most promising avenues for the transformation of the current transportation economy lies in the discovery and coupling of novel routes in the large-scale generation of renewable hydrocarbon fuels. Recent scientific reports have shown that the photocatalytic and electrochemical reduction of CO2 can be efficiently achieved with high specificity, which has triggered a special interest in this particular reaction as a way leading to renewable fuels generation. Despite the advances, the underlying mechanism of the photocatalytic processes and how these correlate with materials surface properties remain poorly understood, which has hindered the rapid development of photocatalysts for the production of hydrogen and hydrocarbon from CO2 and water. Using an advanced set of in-situ spectroscopy techniques, this research aims at advancing our fundamental understanding of the effect of the surface chemistry on the photocatalytic CO2 reduction performance and material properties of current promising visible light-active photocatalysts, and therefore providing useful design guidelines for future materials synthesis.