Preparation And Application Of Metal/Non-metal Doped Carbon Quantum Dots

As a new type of nano carbon material,carbon quantum dots(CQDs)show excellent photoluminescence,good water solubility,low biological toxicity,and photoinduced charge transfer.These properties have attracted extensive attention in the fields of photocatalysis,biosensor,heavy metal ion detection,and lithium ion battery.Based on deep eutectic solvents(DESs),two sorts of metal/non-metal doped CQDs were prepared by using hydrothermal method and combustion method.The photocatalytic performance of Cu@CQDs was investigated.The research contents are as follows:1)The silicon doped carbon quantum dots(Si@CQDs)were compound by hydrothermal method and combustion method respectively.The DES was used as carbon source which was synthesized by lauryl betaine and D-fructose.And tetraethyl silicate was used as silicon source.The preparation effect of Si@CQDs was better with the molar ratio of 1:1.The corresponding hydrothermal temperature and time were 200? and 12 h.It was found that the as-prepared Si@CQDs showed uniform size and good dispersion with average particle size of 5nm.The surface of Si@CQDs contained C-N and C=O functional groups.Then the Si@CQDs was synthesized by the combustion method.The average particle size of as-prepared Si@CQDs was 2.5nm,which aggregated nanoclusters in aqueous solution.2)Three kinds of metal doped carbon quantum dots(M-CQDs)were prepared by hydrothermal method and combustion method.They were Cu@CQDs,Co@CQDs,and Zn@CQDs,respectively.To prepare Cu@CQDs,the metal ligand DES was synthesized by glycerol,choline chloride and copper dichloride as precursors.The molar ratio of raw materials was 5:1:1.When the hydrothermal temperature and time were set as 220? and 24 h,the Cu@CQDs exhibited better fluorescence performance,anti-Stokes effect,and emit blue-green photoluminescence under UV excitation.The Cu@CQDs prepared by the combustion method possessed higher copper doping rate when the preparation temperature and time were 300°C and 3h,respectively.The range of particle size distribution was from 2 to 5nm with good electron transport function.3)The as-prepared Cu@CQDs by combustion method were used as photocatalysis.The surface of Cu@CQDs contained hydrophilic functional groups and nano-copper compounds,which showed excellent photocatalytic properties.Rhodamine-B(RhB)aqueous solution was irradiated under visible light,and photocatalytic performance of Cu@CQDs?~? was studied.The results revealed that Cu@CQDs performed excellent photocatalytic performance with the RhB degradation rate of 95%.