Surface Modification Of Boron-Doped Diamond And Its Electrochemical Application

Boron-doped diamond(BDD)as a new type of functional material not only has excellent mechanical properties and good physical-chemical stability,but also has many superior electrochemical properties,such as wide electrochemical potential window,low capacitance and background current as low as close to zero.Due to its many advantages,BDD has broad application prospects in the fields of microelectronics,electrode materials,electrochemical treatment of toxic organics and detection of trace organics.In this paper,BDD film is used as the substrate,and Por-NiFeS/Ni/BDD electrode is constructed by electrodeposition of nickel-iron sulfide,which is applied to explore seawater electrolysis.In addition,Ni(OH)₂/BDD sensor is synthesized by electrodepositing Ni(OH)₂ to explore its application in glucose detection.The seawater environment contains a large amount of Cl^-ions,which will cause severe corrosion to electrode materials,so materials with high chemical stability are required as electrodes.The Por-Ni/BDD electrode with 3D porous structure is constructed by electrodepositing nickel on the BDD film using a hydrogen bubble dynamic template,and then the Por-NiFeS/Ni/BDD electrode is prepared by cyclic voltammetry electrodeposition of nickel-iron sulfide.In simulated seawater(3.5%NaCl in 1 M KOH),the electrode exhibited excellent electrocatalytic performance of 169 and 277 mV to achieve 10mA cm^-2for hydrogen evolution reaction(HER)and oxygen evolution reaction(OER),respectively.And in 1 M KOH real seawater,Por-NiFeS/Ni/BDD showed 81.2%and 87.5%of the original current density(10 mA cm^-2)for HER and OER,respectively after 50 h stability test.Due to the wide range of electrochemical potential window,low background current,outstanding electrochemical stability and a series of excellent performances,BDD is very suitable as a substrate material for electrochemical detection sensors.In this paper,BDD was used as the substrate,and Ni(OH)₂/BDD sensor was prepared by constant potential deposition of catalytically active Ni(OH)₂ for glucose detection.The results showed that the detection limit was 4.58?M,which was linear in 5-5000?M.The sensitivity in the range is0.704 mA m M^-1 cm^-2.In order to further improve the detection performance,high-temperature metal catalytic corrosion was performed on BDD to increase its specific surface area.The Ni(OH)₂/E-BDD sensor was prepared by the same constant potential deposition on the etched BDD substrate for glucose detection,which improved the detection limit and sensitivity.Its detection limit is 2.23?M,the sensitivity in the linear range of 0.005-5 m M is 1.450 mA m M^-1 cm^-2.