Cu2O/Ti3C2MXene heterojunction photocatalysts for improved CO2 photocatalytic reduction performance

Abstract Photocatalytic CO2 reduction has been viewed as a promising approach to relieve the energy crisis and green-house effect. Cheap and high performance cocatalyst is an effective approach to enhance the photocatalytic activity. Ti3C2Tx (MXene) is a new family of 2D layered materials, which can be served as an electron conductor. In this work, Cu2O/Ti3C2Tx heterojunction composites were prepared by in situ hydrothermal growth method. Cu2O/Ti3C2Tx with the different percentages of ultrathin Ti3C2Tx (2, 5, 10, 20 and 30 mg) nanosheet in the heterostructured catalysts are noted as CuTi-X (X = 2, 5, 10, 20, 30). As prepared CuTi-10 exhibits the highest photocatalytic CO2 reaction activity (17.55 μmol·g−1·h−1 for CO and 0.96 μmol·h−1·g−1 for CH4), which is 3.1 and 4.0 times higher than that of pure Cu2O (5.73 μmol·g−1·h−1 for CO and 0.24 μmol·g−1·h−1 for CH4, respectively). The advantage of the in situ growth endows the Cu2O/Ti3C2Tx heterojunction contact interface, which is conductive to the separation of photogenerated electrons-hole pairs. The main reason is analysed and can be attributed to that Ti3C2Tx can served as an electron acceptor due to its excellent conductive properties, rendering that more photo generated electrons attend the CO2 reduction reaction. This provides a strategy to construct the Cu2O/Ti3C2Tx heterojunction for photocatalytic CO2 reduction.