B-doped single crystal diamond（BDD) —— Novel environment-friendly electrode materials in organic wastewater treatment

BDD is a diamond material in which some of the carbon atoms in diamond are replaced by boron atoms. Because the intrinsic resistance of diamond can reach 1016 Ω∙cm, it is an insulating material with excellent performance. When boron atoms are doped into diamond，diamond transforms from an insulator to a semiconductor. This is because boron atoms enter the diamond lattice to generate hole carriers, making it a hole-type semiconductor or a P-type semiconductor. With the increase of boron doping concentration, diamond The hole concentration in the stone increases accordingly, the carrier concentration increases, and the conductivity improves. However, when the concentration of boron atoms in diamond is too high, the structure of diamond will be destroyed, resulting in a significant reduction in the conductivity of diamond. Under the condition of electrification, the surface of BDD will directly or indirectly oxidize the organic matter in the water into non-toxic and harmless inorganic matter.

Studies have shown that BDD is an environmentally friendly new electrode material, and the electrochemical method as an anode has shown good removal effects on a variety of difficult-to-degrade organic pollutants and macromolecules such as dyes, pesticides, antibiotics, endocrine disruptors, etc., almost all of which can be fully mineralized, and it is an environmentally friendly pollution treatment method which has received increasing attention.

The electrochemical oxidation method using boron doped diamond (BDD) as the electrode can rapidly and efficiently degrade organic matter in wastewater by generating hydroxyl radicals (-OH) with strong oxidizing properties in water, which has the widest electrochemical window, very high oxygen-dissolving potential, excellent chemical stability, and can be operated continuously for a long time in a strong acidic, alkaline, and high-salt environment, and it is expected to become the promising organic wastewater treatment technology.

Single crystal diamonds produced by CSMH can be doped from low to high B-concen.trations. The lightly B-doped diamond exhibits good mobility, suitable for semiconductordevices. Heavily B-doped diamond demonstrates low resistivity and can be used as anelectrode for ohmic contacts.

CSMH uses the MPCVD method to prepare large-sized and high-quality diamonds, and currently has mature products such as diamond heat sinks, diamond wafers, diamond windows, diamond heterojunction integrated composite substrates, etc. Among them, the thermal conductivity of diamond heat sinks is 1000-2200W/(m.k), and the surface roughness of diamond wafer Ra<1nm. It has been applied in aerospace, high-power semiconductor lasers, optical communication, chip heat dissipation, nuclear fusion and other fields.