Synthesis Of Carbon Quantum Dots By Fenton Method Assisted By Ultrasonic Microwave And Its Optical/electrical Properties

Carbon Quantum Dots(CQDs)were new zero-dimensional nanomaterial composed of dispersed spherical carbon particles with extremely small size(below 10 nm).Due to the small size,luminescence,low toxicity,light stability,light of bleaching reduction,biocompatibility,electrocatalysis,multiphoton excitation,up conversion photoluminescence and chemiluminescence have attracted much attention.The excellent luminescence performance has made CQDs widely used in the field of ion detection.In addition,CQDs composite catalytic materials have also become electrical due to their unique physical and chemical characteristics of controllable morphology and controllable microstructure.This type of catalytic material has shown excellent electrochemical conversion efficiency.In this paper,CQDs based on petroleum coke was prepared by advanced oxidation technology,and a series of characterization and cobalt ion detection were carried out.The application of MoS2/CQDs composite material in electrocatalytic hydrogen evolution was also studied.The main research contents can be summarized as follows:1.Preparation of petroleum coke-based CQDs by advanced oxidation technology and its detection of cobalt ionUsing petroleum coke as the precursor,CQDs were synthesized by a simple microwave ultrasonic method assisted fenton method,which have excellent photoluminescence properties.The emission spectrum of CQDs was almost independent of the excitation wavelengths in the range of 270 to 370 nm,and has the strongest fluorescence emission centered at 350 nm.Due to the electron transfer rate and coordination interaction between CQDs and cobalt ion,CQDs were used as selective fluorescent probes for the determination of cobalt ion.The research results showed that:under the optimized experimental conditions,CQDs displayed a good linear relationship in the range of 100-1000 ?M,R2=0.9937,the detection limit was 79.76 ?M,and the quantum yield was 3.837%.2.Preparation of MoS2/CQDs and application in electrocatalytic hydrogen evolution reactionLamellar molybdenum disulfide(MoS2)was synthesized by hydrothermal method.MoS2 and CQDs were combined by charge adsorption.TEM and HRTEM results confirmed that the binary MoS2/CQDs complex was successfully synthesized.XRD results showed that the crystallinity of MoS2/CQDs composites was poor.The hydrogen evolution reaction(HER)of the synthesized samples was tested.The results of linear sweep voltammetry(LSV)showed that the HER activity of MoS2/CQDS composites was significantly improved when compared with pure MoS2.Among them,MoS2/CQDs-2(mass ratio of MoS2 to CQDs is 5:2)had the best HER activity whose overpotential was 208 mV and its Tafel slope was 94 mV/dec.Figure[38]table[5]reference[124]...