Electrosynthesis Of B₂O With Diamond-like Structure At Ambient Temperature And Pressure

Boron suboxide especially diamond-like B₂O is one of the important new superhard materials.Although many methods for synthesis of diamond and cubic-boron nitride at ambient temperature and pressure had been established, diamond-like B₂O can be only synthesized at high temperature and pressure. According to the mechanism of solvothermal synthesis of diamond,a new principle for electrosynthesis of diamond-like B₂O at ambient temperature and pressure was put forward with its mechanism still remaining unclear.It is obvious that to find cheaper way to synthesize diamond-like B₂O and reveal its reaction details are of both theoretical and practical importance.In this dissertation,the synthesis progress of diamond and boron suboxide are summarized at first.The electrosynthesis of diamond-like B₂O at ambient temperature and pressure by electrolysis of[BMIM]BF₄ as electrolyte was analysed in detail. Based on the electrosynthesis principle of diamond and the experiment for electrosynthesis of B₂O,the mechanism of electrosynthesis of diamond-like B₂O was studied by examining the factors that affect the reaction.A conventional three-electrode cell with CH₃CN—(Bu)₄NBF₄—(Bu)₄NCl serving as new electrolyte system was used so as to get rid of the effect of adsorbed moisture.Potentiostatic synthesis of diamond-like B₂O was conducted using an HDV-7 potentiostat with CHI604A electrochemical analyzer for monitoring the electrolysis process.XRD, SEM and EDS were used for characterization of the products.The result shows that there is only a little B₂O crystal but a large amount of amorphous element boron present in the product.This means the oxygen source is very important for synthesis of B₂O.Silver with its crystal structure similar to that of B₂O also so takes crucial roles in electrosynthesis of B₂O.A novel route to introduce oxygen source was established,which is helpful for revealing the reaction mechanism of electrosynthesis.This dissertation presents a second system for electrosynthesis of diamond-like B₂O at ambient temperature and pressure.And more evidences for mechanism study for the synthesis were presented.Both of these are very important for further study of synthesis of diamond-like of the B₂O.