Ball-flower like NiO/g-C3N4 heterojunction for efficient visible light photocatalytic CO2 reduction

A ball-flower like NiO/g-C3N4 heterojunction composite was synthesized via a hydrothermal deposition method combined with subsequent calcination route. The NiO/g-C3N4 heterojunction exhibited a superior performance in CO2 photoreduction. A maximum CO yields of 4.17 μmol/(h g-cat) had been obtained on 40% NiO/g-C3N4 composite, which was 2.5 and 7.6 times as high as the pure g-C3N4 and NiO respectively. The promotion mechanism could be ascribed to the perfect band matching and efficient internal charge transfer within the p-n junction, which results in high-efficiency separation of photogenerated electron-hole pairs, strong visible-light response and high specific surface area.