Preparation of Iron‐Doped Carbon Dots and Their Application in Photocatalytic Reduction of Carbon Dioxide

Abstract Photocatalytic carbon dioxide (CO 2 ) reduction technology is considered a promising approach to alleviate greenhouse gas emissions in the earth's atmosphere. Carbon dots (CDs), which possess good optical properties, are of keen interest in the field of photocatalysis. Iron (Fe), a transition metal element with vacant 3d orbital that contributes to the electron‐transfer process, is a promising metal dopant for CDs that allows for the preparation of multifunctional CDs. Fe‐doped carbon dots (Fe−CDs) were synthesized using ethylenediamine tetraacetic acid disodium (EDTA‐2Na) and ferric chloride (FeCl 3 ⋅ 6H 2 O) through a simple one‐step hydrothermal method. The chemical structure of the obtained Fe−CDs was studied, and their activity for the photocatalytic reduction of CO 2 was tested. The results show that Fe doping amount of 13.0 wt.% is the most favorable for the photocatalytic reaction. The maximum photocatalytic reduction of CO 2 to methanol reaches 654.28 μmol ⋅ g −1 ⋅ h −1 within 6 h, which is about 2.6 times of the methanol yield of CDs, which is attributed to high electron transfer rate of Fe dopant.