Construction Of Cobalt-Nickel Diatomic Catalyst For Hydrogen Peroxide Production And Degradation Of Pollutants By Electrofenton

As one of the most important chemicals in industry,hydrogen peroxide（H₂O₂）is widely used in medical treatment,bleaching,sewage treatment and industrial synthesis.At present,the synthesis of hydrogen peroxide（H₂O₂）mainly relies on the energy-intensive anthraquinone process,which not only produces a complex process and waste pollutants,but also poses huge requirements and challenges for storage and transportation due to the high concentration of hydrogen peroxide（H₂O₂）.Therefore,There is an urgent need to find a low-cost,environmentally friendly and safe way to synthesize H₂O₂.Compared with the industrial anthraquinone process,electrochemical catalytic oxygen reduction（ORR）is a green and safe way to synthesize hydrogen peroxide in situ and on a small scale.Due to their low cost,biofriendliness and flexible structure modulation,carbon-doped catalysts are considered to be economical and effective catalysts for the production of hydrogen peroxide（H₂O₂）by electrochemical two-electron oxygen reduction reaction（ORR）.The construction of atomic-level catalysts based on carbon-based materials with high atomic efficiency and definite structural properties is considered to be the most potential ORR catalysts,and is also the latest research topic.Therefore,a biatomic active site synergistic oxygen-nitrogen co-doping atomic-level catalyst was designed and prepared in this paper,which can be used to produce hydrogen peroxide in cathode oxidation efficiently and degrade pollutants in situ.At the same time,the anode and cathode are coupled with the synthesized Sn₃O₄integrated electrode to produce hydrogen peroxide and react with benzyl alcohol oxidation to realize the effective utilization of anode to achieve the purpose of energy saving,emission reduction and green environmental protection.The main research contents of this paper are as follows:（1）The oxygen-nitrogen co-doped bimetallic atomic catalysts（Co/Ni-SACs）with honeycomb structure supported on the GO layer were successfully synthesized by adsorption of Co and Ni metal sources with the support on the carbon-based precursor through high temperature calcination,which were used for the high efficiency electrocatalytic oxygen reduction（ORR）synthesis of H₂O₂in alkaline solution.The Co/Ni-SACs metal and atomic state are evenly dispersed on the carbon substrate,the Co/Ni diatomic synergism and the coordination environment of N and O elements make the catalyst have excellent electrocatalytic activity.In the range of0-0.6 V vs.RHE,the selectivity of H₂O₂can reach 80%when 1 mmol/L CTAB is added to 0.1 mol/L KOH solution.The yield of hydrogen peroxide was measured at the optimal potential of 0.4 V vs.RHE,and the cumulative yield reached 7377.4 m mol/L g_cat^-1for 5 h,indicating that Co/Ni-SACs had good H₂O₂intrinsic activity and yield in alkaline solution,and could still maintain a high yield of hydrogen peroxide after 24 h reaction and good stability.Co/Ni-SACs and stainless steel mesh（SSM）constructed a double-cathode electrofenton system for degrading dyes,antibiotics,heavy metals,pesticides and other pollutants in 0.1 mol/L Na₂SO₄（p H=3）solution.The effects of electrolyte p H and applied potential on the degradation efficiency of pollutants were explored.The constructed device can show rapid pollutant removal rate and good recyclability.In addition,the existence of hydroxyl radical（·OH）was determined by fluorescence method.Tert-butanol was used as the trapping agent to further explain that hydroxyl radical（·OH）was the main active substance in the degradation process,and the mechanism of the degradation process was discussed.This study is of great significance for the synthesis of diatomic catalysts for electrocatalytic synthesis of H₂O₂and degradation of pollutants by electrofenton system.（2）A battery system was successfully constructed in which both anode and cathode produced hydrogen peroxide.By optimizing the reaction conditions such as electrode potential,the optimal reaction conditions were determined to achieve low energy consumption and high efficiency synthesis of hydrogen peroxide system.By comparing different catalysts,different electrolyte,potential and other parameters were optimized.Finally,Sn₃O₄/NF was used in the anodic water oxidation reaction at the optimal potential of 2.3672 V vs.RHE,and the cumulative yield in 0.1 mol/L KOH solution for 30 min could reach 76.1μmol/L,with good cycling and stability.Co/Ni-SACs and Sn₃O₄/NF construct the battery,which can realize the coupling of anode and cathode while electrocatalyzing the production of hydrogen peroxide,effectively reducing the potential.Under the optimal potential of 0.2 V vs.RHE,the total output of anode and cathode in 6 h can reach 11938.9μmol/L,realizing the efficient synergistic effect of cathode and anode.It is of reference significance for the preparation of high efficiency electrocatalyst for the synthesis of hydrogen peroxide by water oxidation and the coupling of battery.Construct the battery system of yin-yang pole linkage.By comparing the oxidation effects of M NPs@Co/Ni-SACs/NF on different objects,the influences of different materials,BA concentration,KOH concentration and other parameters on benzyl alcohol oxidation reaction（BOA）were explored.In 0.1mol/L KOH solution containing 0.1 mol/L BA,the constant-current method was used to control the current density(30 m A cm^-2)for 2 h.The conversion rate of BA could reach 70%and the selectivity of BAD was close to 99%,indicating that M NPs@Co/Ni-SACs/NF could selectively oxidize BA to BAD.In the H-type electrolytic cell,the battery reaction is driven at the same time,and the optimal cathode potential is selected to drive the anode reaction.Under the applied potential of 0.4 V vs.RHE,the output of the cathode for 2 h is 3329.34 mmol/L g_cat^-1,and the conversion rate of the anode for 2 h BA is 60%.It is important for anode increment and anode and cathode coupling to save energy consumption.