Preparation Of Porous Electrode Materials And Study On Electrocatalytic Oxidation Of Formaldehyde In Aqueous Solution

Formaldehyde is a substance harmful to the environment and human body.The electrocatalytic oxidation technology to treat formaldehyde in wastewater is stable,convenient and efficient.The use of nanoporous materials as electrodes can further enhance the effect of electrocatalytic oxidation technology on the removal of formaldehyde.In this paper,two materials of nanoporous gold and nanoporous copper are made,and the composition and structure of the materials are understood through the characterization of the materials,and then the two materials are used in the electrocatalytic oxidation of formaldehyde in aqueous solution,the specific conclusions are as follows:（1）The gallium film is coated on a smooth gold sheet and a smooth copper sheet,heated to form a gold-gallium and copper-gallium alloy precursor,and then electrochemical dealloying method is used to remove the gallium component in the precursor to form nanoporous gold,Nano porous copper material.The prepared nanoporous materials were characterized by XRD,SEM,N₂-adsorption-desorption,and electrochemical testing techniques.The results showed that after electrochemical dealloying,the surface grains of nanoporous gold and nanoporous copper materials were refined and formed Nano-porous structure greatly improves electrochemical activity.（2）Cyclic voltammetry was used to study the oxidation-reduction reaction of nanoporous gold and nanoporous copper materials in aqueous formaldehyde solution.According to the results of cyclic voltammetry,the appropriate potential was selected,and the electrocatalysis of formaldehyde in aqueous solution was studied by constant potential electrolysis.Oxidation.The research results show that the nanoporous gold electrode electrocatalyzes the oxidation of formaldehyde in the aqueous solution,and the electrolytic current generated at+0.50 V（vs Hg/Hg O）potential is about-1.3 m A·cm^-2;while the nanoporous copper electrode electrocatalytic oxidation When formaldehyde is in an aqueous solution,the electrolysis current generated at+0.54V（vs Hg/Hg O）potential is approximately-1.9 m A·cm^-2.In the electrocatalytic oxidation process of nanoporous gold and nanoporous copper materials,the electrode reaction conforms to the transient diffusion model.（3）Since copper materials are cheaper than gold materials,this paper chooses nanoporous copper as the working electrode and ion-exchange membrane electrolyzer as the electrolysis device.Under constant potential,the electrocatalytic oxidation efficiency of the electrode material on formaldehyde is further studied.The research results show that at+0.54 V（vs Hg/Hg O）potential,the nanoporous copper electrode continuously electrocatalyzes the oxidation of 10 m M formaldehyde aqueous solution for 500 min,the degradation efficiency of formaldehyde reaches90%,and the process is continuous and stable.（4）Using the ion-exchange membrane electrolyzer as the electro-chemical synergistic catalytic reactor,under the condition of the short-circuit potential of the two electrodes,the electro-chemical synergistic catalytic oxidation effect of the nanoporous copper electrode combined with the oxidant was further studied.The research results show that at 0 V（vs Hg/Hg O）potential,the oxidant in the cathode chamber is associated with the formaldehyde in the anode chamber through the electrode and external circuit,and has an electrocatalytic oxidation effect on formaldehyde.The order of oxidant effect from strong to weak is:ammonium persulfate>hydrogen peroxide>oxygen,and the amount of oxidant used is controlled by the concentration of formaldehyde.