Designing Eco-functional Redox Conversions Integrated in Environmental Photo(electro)catalysis
Shi Nee Lou, Jonghun Lim, Tae Hwa Jeon, Wonyong Choi
Abstract
The global circulation and transformation of resource/energy and the self-cleaning of contaminated environments are largely driven by solar radiation through various photochemical and photosynthetic mechanisms. Photo(electro)catalysis is an active engineering method that mimics nature's solar conversion processes and is being intensively investigated as a key technology that can provide solutions for sustainable development. However, because the majority of photo(electro)catalysis is focused on the oxidative (or reductive) conversion of a target compound, which underutilizes the power of the counter charge carrier, the solar materials and reactions need to be systematically designed and implemented to make the photosystems more practically viable. This perspective describes an integrated approach that combines the oxidation and reduction conversions of various organic and inorganic substances in a single system by carefully designing photocatalytic materials and systems. The ideal integrated photo(electro)catalytic process should utilize both the oxidative and reductive powers of semiconductors in their full capacity to make the overall process more photoefficient and less demanding of external chemical inputs such as auxiliary oxidants and reductants. We introduce various photo(electro)catalytic redox conversions (e.g., reactive oxygen species, reactive halogen species, hydrogen peroxide, nitrate, and ammonium) and their combinations and discuss challenges and perspectives in realizing solar-based environmental remediation.