Photoelectrochemical Characteristics Of Cuprous Oxide-based Metal Foam Electrode And Its Application In Ion Detection

As a new detection method,the photoelectrochemical(PEC)detection can separate the excitation source signal from background signal.The PEC detection exhibits high sensitivity as well as low background.In sensing approach,the PEC is recently developed and represents several attractive features and significant progress in biology,medicine,environmental monitoring.The core of PEC detection is to find photoactive materials and sensitive detection electrodes.Firstly,the semiconductor nanomaterials are the most promising photoactive materials for photoelectric detection due to their controllable band gap and conductivity.Secondly,the metallic foams have become one of the candidate materials for photoelectrochemical detection electrodes because of their good conductivity and light transmittance.In this thesis,a high-performance copper oxide-based foam copper electrode was prepared.The main works are as follows:Cuprous oxide electrodes were rapidly prepared by electrochemical deposition on highly conductive foamed copper substrates,then we investigated the effect from deposition voltage,deposition temperature,and test bias on the electro-optical properties of cuprous oxide/foam copper electrodes.Afterwards,we designed and prepared the PEC characteristics testing device to study the influence of the switching time of the device.In addition,we investigated the conductivity type and photoelectric response ability of the electrode by the transient photocurrent response testing technology.The resulting photocurrent density of the optimized electrode reached 128 ?A/cm2.After that,we investigated the influence of electrodeposition temperature and electrode holding time after deposition on the growth of copper hydroxide quantum dots.The experiments show that the synergistic action of the linear copper hydroxide quantum dots and the cuprous oxide can separate the photo-generated carriers more quickly and the photocurrent density value can be increased from 128 pA/cm2 to 288 ?A/cm2 after the optimized deposition voltage and so on.Finally,we studied the stability of copper hydroxide/cuprous oxide/copper foam electrode.It is observed that the photocurrent density retention rate exceeded 90%at 1000s optical switch,indicating that the stability of the electrode was pretty good.In this experiment,we prepared graphene oxide(rGO)by electrochemical deposition on a foam copper substrate in order to increase the specific surface area of the substrate and adjust the microstructure of the substrate,so that the electrode can carry more photoelectric active material.The preparation conditions for graphene-modified copper oxide quantum dots/cuprous oxide/foamed copper electrodes are the same as cupric hydroxide quantum dot/cuprous oxide/cupric electrode.We investigated the effects of rGO with different thicknesses on the PEC response characteristics of the electrode experimentally.They are characterized by scanning electron microscopy,transmission electron microscopy and UV-vis absorption spectroscopy.The results demonstrated that foam copper can support more photoelectric active material than ITO electrode by virtue of the excellent conductivity and wrinkle structure of graphene.After photoelectric test,the photocurrent density reaches 400 ?A/cm2 and maintains good stability under 1000s optical switching,while the photocurrent density of the ITO electrode is only 138 ?A/cm2 and decays continuously.Then,we detected the copper(II)ions in different concentrations by in-situ electrodeposition with the optimal conditions by employing the graphene modified copper oxide quantum dot/cuprous oxide/copper foam electrode.Therefore,the sensing function of copper(II)ions detection is realized.