Preparation And Properties Of Ti/BDD Electrodes By Hot Filament Chemical Vapor Deposition

Diamond has excellent electrical properties, in recent years boron-dopeddiamond (BDD) thin film electrode in electrochemical applications is getting moreand more attention of people. BDD electrode compared with other ordinary electrodehas many outstanding physical and chemical properties, such as high strength, wearresistance, corrosion resistance，good electrical conductivity，wide electrochemicalwindow, high oxygen evolution potential and background current small, difficult toadsorb impurities and good stability. Meanwhile BDD film electrodes in a very badenvironment have a long service life. Titanium as the substrates for BDD electrodehas many advantages: high mechanical strength，non-friable, acid and alkali resistance,cheap, good electrical conductivity and surface can form a very thin oxide filmachieve self-protection. So preparation of high-quality Ti/BDD and as electrode usedin wastewater treatment has great practical significance.By hot filament chemical vapor deposition (HFCVD) process, on the basis of thetotal flow of300sccm, pressure of4kPa a series of flat Ti/BDD electrodes arerespectively studied：the distance samples with filament, methane flow rate，boronflow rate and gas pressure on the quality of the BDD film. Using SEM, XRD andRaman spectroscopy, three kinds of commonly used characterization methods in thequality of thin film are analyzed, and found the optimal deposition conditions: thedistance10mm, methane flow3sccm, boron flow1、3、5sccm. Finally throughbetween the heater and substrate with dc bias, prepared a higher quality of thin filmelectrode. Bias parameters is studied, the bias of50V when the growth of thin filmgrain closer and quality is better. Then used the optimal condition have growth acontinuous and not loose BDD film on porous Ti.The performance of Ti/BDD electrodes are tested by electrochemicalmeasurement system. The electrochemical window of flat Ti/BDD electrode afterHFCVD method optimized conditions is3.6V, small background current close tozero. Porous Ti/BDD electrode electrochemical window is3.4V, but the backgroundcurrent is larger than flat electrode, it is probably due to its special porous structure.Finally, we studied the Ti/BDD electrode on the degradation of low concentration of phenol solution, results show that the Ti/BDD electrode of the CODremoval rate and the ICE is higher, eight hours when the removal rate of CODreached75%, initial ICE value reached40%. COD removal rate of flat electrode andporous electrode and ICE are compared, the porous electrode of the preparation oftitanium substrate degradation rate faster and lower energy consumption, inwastewater treatment applications than the flat substrate may have more advantages.In a word, by changing the experimental parameters to find the right conditionsfor the preparation of Ti/BDD electrode, the phenol degradation show that theelectrode degradation effect and low energy consumption. BDD film is a kind of verygood electrode material.