Photocatalytic Conversion of CO₂ into Renewable Hydrocarbon Fuels: State‐of‐the‐Art Accomplishment, Challenges, and Prospects

Abstract

Photocatalytic reduction of CO2 into hydrocarbon fuels, an artificial photosynthesis, is based on the simulation of natural photosynthesis in green plants, whereby O2 and carbohydrates are produced from H2 O and CO2 using sunlight as an energy source. It couples the reductive half-reaction of CO2 fixation with a matched oxidative half-reaction such as water oxidation, to achieve a carbon neutral cycle, which is like killing two birds with one stone in terms of saving the environment and supplying future energy. The present review provides an overview and highlights recent state-of-the-art accomplishments of overcoming the drawback of low photoconversion efficiency and selectivity through the design of highly active photocatalysts from the point of adsorption of reactants, charge separation and transport, light harvesting, and CO2 activation. It specifically includes: i) band-structure engineering, ii) nanostructuralization, iii) surface oxygen vacancy engineering, iv) macro-/meso-/microporous structuralization, v) exposed facet engineering, vi) co-catalysts, vii) the development of a Z-scheme system. The challenges and prospects for future development of this field are also present.

Z‐Scheme Photocatalytic Systems for Promoting Photocatalytic Performance: Recent Progress and Future Challenges

“…Several reviews related to Z‐scheme water splitting have been reported,4, 8, 12 and all‐solid‐state Z‐scheme photocatalytic systems without redox pair were especially summarized, which mainly exhibit the obvious differences of all‐solid‐state Z‐scheme systems in the preparation methodology, working mechanism, properties and application 7. Some Z‐scheme examples were also partly presented in our previous reviews about heterostructured photocatalysts3 and CO 2 photoreduction 15…”

CO2 Reduction: From the Electrochemical to Photochemical Approach

“…Several previous high‐quality review articles on similar topics are available 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26. Given the recent heightened research activities and increasingly deepened understanding of these two processes, we believe that an up‐to‐date account on their status and existing challenges is necessary so as to provide readers with a current snapshot of this rapidly evolving area.…”

In situ synthesis of ordered mesoporous Co-doped TiO2 and its enhanced photocatalytic activity and selectivity for the reduction of CO2

“…CO, CH 4 ) which is generally less than tens of μmol per hour of illumination per gram of photocatalyst. 11,12 In artificial photosynthesis, the semiconductor should have appropriate conduction band minimum for the reduction half-reaction and valence band maximum for the oxidation half-reaction. Therefore, the main components of the common photocatalysts for CO 2 36,37 are quite difficult to promote the oxidation half-reaction, which leads to the generation of oxygen through the oxidation of water.…”