Preparation of Mo2CTx MXene as co-catalyst for H2 production by etching of pure/mixed HBr solution

Mo2CTx is a novel co-catalyst to enhance the photocatalytic performance of CdS for H2 production. The surface of Mo2CTx is usually terminated by fluorine anion because it is generally made by the etching of fluoride-containing solution. Here we report, a novel method to prepare highly pure MXene with Br termination by the etching of pure HBr at 220 °C for 3 d, or the HBr solution mixed with LiBr, NaBr, KBr or NH4Br at 180 °C for 24 h. The pure HBr etching needs higher temperature and longer time to make pure Mo2CTx, however, which result lager interlayer space and more active sites. All the Mo2CTx samples show high co-catalytic performance to enhance the photocatalytic performance of CdS for H2 production. The H2 production rate of CdS combined with HBr etched sample was 17,566 μmol g−1 h−1, similar with the sampled combined with traditionally HF etched sample. This is the first report to prepare MXene by etching of Br containing solution. The Mo2CTx made by this method is terminated by Br/O without F, and show excellent co-catalytic properties.