Photoelectrochemical Properties and Its Application of Nano-TiO2/Boron-doped Diamond Heterojunction Electrode Material

Like titanium dioxide (TiO2), boron-doped diamond (BDD) is one of the most popular functional materials in recent years. In this work, TiO2/BDD heterojunction electrodes were prepared by dip-coating TiO2 nanoparticles onto BDD electrodes. XRD patterns of these electrodes suggest that the mixed-phase TiO2/BDD heterojunction electrode with anatase and rutile can be obtained at 700 degrees C, named as mixed-phase TiO2/BDD electrode. However, the TiO2/BDD heterojunction electrode prepared at 450 degrees C has only anatase phase TiO2, named as pure-anatase TiO2/BDD electrode. SEM images indicate that TiO2 nanoparticles with ca. 20 nm were both immobilized continuously and uniformly onto the BDD electrode whether at 700 degrees C or 450 degrees C. The photoelectrocatalytic activity of mixed-phase TiO2/BDD electrode is 3-fold of that obtained at pure-anatase TiO2/BDD electrode, indicating that mixed-phase TiO2/BDD electrode is more effective to use to degrade and/or detect the organic compounds. Comparing with the TiO2/ITO electrode, the TiO2/BDD electrode presents an excellent chemical stability. The detection of glucose and KHP in the solution indicates that the steady-state net photocurrent in the range of concentration monitored presents superiorly linear relationship to the concentration of glucose and KHP. Therefore, the mixed-phase TiO2/BDD electrode may be used as a high effective sensing material for the detection of organic compounds.