The effect of green carbon Dots/Titanium dioxide for photocatalytic reduction of CO2

Abstract

Abstract With the rapid rate of industrial modernization, the continuous emissions of carbon dioxide (CO 2 ) are greatly disturbing the natural carbon balance and contributing to global warming. To mitigate this effect, photocatalytic reduction of carbon dioxide has gained popularity as a means of converting it into useful products. This study examined the photocatalytic reduction of aqueous CO 2 under ultraviolet irradiation (UV) using green carbon dots (CDs) made from pomegranate peel, nano titanium dioxide (TiO 2 ), TiO 2 /CDs composite, and metal-loaded carbon dots-modified titanium oxide (Cu-CDs/TiO 2 ). The reduction of CO 2 gas in water was carried out in a batch reactor utilizing the four photocatalysts. In order to verify the catalysts’ functional groups, nanoscale shape, and composite production, FTIR and TEM were used for characterization. The findings demonstrated that oxygenated products were preferred by pure CDs, but the performance of TiO 2 was very pH dependent, with ester formation being promoted in acidic environments and CO formation in alkaline ones. An increase in CO selectivity resulted from the TiO 2 -CDs composite’s enhanced charge separation and electron transfer; a change toward decreased hydrocarbons in product distribution was brought about by the addition of Cu, which opened hydrogenation pathways.