5.Photocatalytic Carbon Dioxide Reduction

Photocatalytic reduction of carbon dioxide is one of the promising technologies which transforms carbon dioxide into valuable chemicals utilizing solar energy. This process is also called as artificial photosynthesis since it uses carbon dioxide, water in either vapor or liquid phase, and solar energy to produce carbonaceous products in the presence of a photocatalyst. Photocatalytic conversion of carbon dioxide into solar fuels not only helps to reduce adverse effects of carbon dioxide in the atmosphere but also provides an alternative energy storage.

The photocatalytic carbon dioxide reduction is usually conducted in gas or liquid phase. It has been reported that carbon monoxide and methane are the main products in the gas phase system, while methanol, acetic acid, and formic acid are products of the liquid phase system (Z. Fu et al., 2019).

Numerous studies have been conducted to attain highly efficient photocatalysts for carbon dioxide reduction process. However, it still has low solar conversion efficiency due to the recombination of excited electrons and holes, slow charge movement during reduction-oxidation reactions, and ineffective light usage (Low et al., 2016).

Photocatalytic conversion of carbon dioxide into solar fuels is a complicated process which includes reduction of carbon dioxide, proton transport and hydrogenation steps resulting in different carbonaceous products. Hence, it is essential to understand basic mechanism of photocatalytic activity (Khan and Tahir, 2019).

In our group, perovskites are used as semiconductors since it is easy to modify their electrochemical properties. The study is focused on Ti and Ta based perovskites. Different perovskite preparation methods such as solid-state, hydrothermal synthesis, homogeneous precipitation, sol-gel are being conducted.