Preparation Of Boron-doped Diamond Electrode And Its Study Of Electrochemical Ozone Production

As an environmentally friendly strong oxidant,ozone is widely used in food treatment,wastewater treatment,etc.Boron-doped diamond（BDD）has exceptionally high oxygen evolution potential,strong corrosion resistance and excellent electrochemical stability,and is considered an ideal anode material for electrochemical ozone production（EOP）.The performance of BDD for EOP is closely related to the doping level of boron atoms and surface state（including surface morphology and composition）.Therefore,this paper systematically investigated the effects of doping levels and surface state on EOP performance.（1）BDD with different boron doping levels was prepared via hot-filament vapor deposition.The effect of boron doping levels（[B]）on EOP performance was systematically first studied.The results showed that as[B]increased,the grain size of BDD became smaller and the oxygen evolution potential（both greater than 2.2 V vs.Ag Cl）showed a decreasing trend,and the electrochemically active surface area（ECSA）experienced an intial increase and then leveled off.When[B]reached 2.03×10²¹ atoms cm^-3,the BDD electrode had the largest ECSA and the best EOP performance compared to the other BDD electrodes.（2）The surface state of BDD electrode,modified via oxygen plasma etching,on EOP performance was systematically studied.Porous BDD electrodes with different surface states were obtained by adjusting the etching temperature and time,and the oxygen evolution potential is around2.3～2.4 V vs.Ag/Ag Cl.The results showed that when slightly etched,the BDD electrode surface presented a typical diamond structure,and the ECSA increased by 4.72 cm²;when moderately etched,the BDD electrode surface presented a micro-nano porous diamond surface structure,and the ECSA increased by 7.07 cm²;when heavily etched,the surface grain structure was completely destroyed,and the ECSA remained almost the same as the original BDD with only 2.92 cm².（3）The EOP test results showed that the moderately etched BDD(etching temperature and time were 700°C and 2 min respectively,denoted as p-BDD_2min)generates ozone concentration up to a maximum of 9.48 mg L^-1.Under the same unit energy consumption,the EOP performance of p-BDD_2min is 3.76 times that of the original BDD.The current density of p-BDD_2min maintained 95.8%of initial value after a forty-hour long-term test.Compared with other conventional electrodes,p-BDD_2min exhibited excellent long-term stability and EOP performance,indicating its certain application potential.