Growth of 3D nanowall-like structures of FeVO4 by controlling reaction rate for effective CO2 reduction using UV-visible light

We report the synthesis of FeVO4 oxide microstructures with a large amount of polar surfaces using a single-step facile chemical method by growing of FeVO4 microstructures. It was found that nanowall-like morphology of FeVO4 transformed into nanorods and dense-like structure with nanosheets. The morphological analysis revealed that nanorods, nanowall-like, deformed nanowalls, and dense nanostructure shapes were formed on the substrate after 5 h, 10 h, 15 h, and 20 h of the reaction, respectively. The structural analysis confirms the formation of dual phases (volume fraction of FeVO4 = 82 % & Fe2O3 = 18 %) inside the grown structures. Photocatalytic CO2 reduction was measured under irradiation with UV-vis light using the structures as catalysts. The nanowall-like structure exhibited exceptional amount of CO (202 & mu;mol g-1) as compared to particulate FeVO4 (9 & mu;mol g-1) and other nanostructures (nanorods = 93 & mu;mol g-1, deformed nanowalls = 82 & mu;mol g-1 and dense nanostructure = 58 & mu;mol g-1). The enhanced performance for 3D (three dimensional) nanowall-like structure was attributed to light scattering, oxygen vacancies, and increased optical absorbance as compared to other morphologies obtained. Along with the morphology, the formation of heterojunction aroused from the dual phase i.e. FeVO4 and Fe2O3 might have contributed in efficient charge separation. Finally, the development of FeVO4 semiconductor applications for CO2 reduction and its use as a new medium for carbon neutralization are made possible by the increase in active sites and electrical conductivity.