Photocatalytic CO₂ Reduction on TiO₂-Based Materials under Controlled Reaction Conditions: Systematic Insights from a Literature Study

Photocatalytic CO₂ conversion to hydrocarbons (sometimes referred to as ‘artificial photosynthesis’), which mimics natural photosynthesis with purely inorganic photocatalysts, has the potential to simultaneously combat the energy crisis and the greenhouse effect. In more than half of all reported studies to date, TiO₂-based materials are used as the photocatalyst. Yet, the reaction conditions and reactor designs employed in previous studies cover a vast range, hindering mutual comparisons of observed activities and selectivity. In this work, a systematic literature study is attempted, including a selection of only such research publications which report experimental conditions of high purity and a proof of the carbon source (blank experiments, ¹³CO₂ isotope labelling or stoichiometric O₂ identification) for CO₂ photoreduction. General trends were then detected and discussed, aiming to guide future research to more efficient photocatalytic systems.