Impact of Black Body Material Enhanced Gas Movement on CO2 Photocatalytic Reduction Performance

Abstract

Gas movement around and/or through the photocatalyst is thought to be an inhibition factor to promote photocatalytic CO2 reduction performance. In this study, a hypothesis is put forward that the natural thermosiphon movement of gases around the photocatalyst can be improved by using black body material/surface. The black body material/surface that is placed underneath the photocatalyst in the reactor would be heated by absorbing light and then this heats up the gases to promote their movement around/through the photocatalyst. The aim of this study is to prove or disprove this hypothesis by conducting CO2 reduction performance of a TiO2 photocatalyst with NH3 under the conditions without black body material (W/O B.B.), with one black body material (W B.B.-1), and with three black body materials (W B.B.-3). The impact of molar ratio of CO2/NH3 on CO2 reduction performance is also investigated. This study revealed/proved that the hypothesis worked and that the CO2 reduction performance is promoted more with W B.B.-3 compared to that with W B.B.-1. The maximum concentration of formed CO with W B.B.-3 is two to five times as large as that under the condition W/O B.B.