Preparation Of Copper-containing Composites And Its Electrocatalytic Dechlorination And Nitrogen Reduction Performance

With the rapid development of the economy and industry,environmental pollution and energy crisis are key issues affecting the sustainable development of mankind.The removal and resource utilization of toxic pollutants is an important way of environmental governance and restoration.Among them,chloronitrobenzene compounds（Cl NBs）are important basic raw materials in the chemical,pharmaceutical,and dye industries.They have carcinogenic,teratogenic,and mutagenic effects,and are characterized by strong genetic toxicity,stable chemical properties,and difficult biodegradability.Unreasonable discharge during production and use will cause serious pollution to the ecological environment of water bodies,threatening ecological safety,and human health.Therefore,the dechlorination and degradation of chlorinated organics or product resources have important practical significance.Besides,another important issue affecting human life is the energy crisis.The development of new energy or energy conversion is an important way to solve the energy crisis.Nitrogen is an abundant element in the atmosphere.Inorganic and organic nitrogen compounds occupy a prominent position in biological,environmental,and industrial processes.The reduction product of nitrogen is ammonia,which is not only the main raw material for organic chemical and fertilizer industries but also can be used as an attractive energy carrier.It can be used as a propellant for rockets and a power source for new energy vehicles.The industrial synthesis of ammonia mainly relies on the traditional Haber-Bosch process.Because this technology needs to be carried out at high temperature and pressure（300～500℃,150～200 atm）,it not only consumes huge energy but also emits a lot of greenhouse gases.Therefore,the development of green,economical,and environmentally friendly toxic pollutant removal and resource utilization,new energy synthesis and conversion technologies have important research and application significance.In recent years,the use of electrocatalytic technology for the dechlorination and toxicity reduction of chlorinated organic pollutants and the reduction of nitrogen to produce ammonia has attracted more and more attention from researchers.Compared with other methods,the electrocatalytic reduction method has more reaction conditions.It is gentle,highly selective,highly feasible,economical,and environmentally friendly.It is a green method with great practical application prospects.In the entire electrocatalytic reduction technology,an efficient and stable electrocatalyst is the key,which determines the dechlorination efficiency,the Faraday efficiency of nitrogen reduction,and the resource efficiency of the product.Therefore,research on the use of electrocatalytic technology to remove chlorinated organic pollutants and realize the utilization of nitrogen reduction and ammonia production has a very important reference value for the actual sewage treatment process and ammonia production process.In this paper,a combination of electrochemical deposition and chemical displacement is used to prepare copper-containing composite materials with high selectivity,high stability,and high catalytic activity;on the one hand,electrocatalytic reduction technology is used to combine Cu-Pd/Ti composite materials with high efficiency and stable structure.Applied to the electrocatalytic dechlorination degradation study of chloronitrobenzene,optimize the parameters of the electrocatalytic dechlorination reaction system,reveal the dechlorination reaction mechanism and pathway of the research system,to improve the conversion rate of aniline and resource utilization.Explore the structure and composition of the Cu/GO/CP composite catalyst,and apply it to nitrogen reduction to synthesize ammonia to improve the Faraday efficiency and ammonia synthesis efficiency of the nitrogen reduction system.The main research results obtained in this paper are as follows:（1）A copper-palladium composite material that is fast,simple,and easy to obtain,green,clean,efficient,and stable,is prepared through the combination of chemical replacement method and electrochemical deposition method.This method has a better electroactive area and electrocatalytic efficiency than a single electrochemical reduction of Pd.The dechlorination efficiency of 2.5-DCNB is increased from 88.2%to 97.1%.（2）The influence of different factors on the degradation of 2,5-dichloronitrobenzene was systematically explored,and the best reaction conditions were obtained as follows:In 0.05 M Na AC electrolyte,when the current density value reaches 2.25 m A/cm²,The dechlorination efficiency of Cu-Pd/Ti within 3 h is as high as 97.1%.（3）The study found that the current density is a key factor affecting the efficiency of dechlorination:the current density is too low to produce enough Hads required for the dechlorination reaction;the higher the current density,the electron transfer speed on the electrode surface The faster it is,the more the HER（Hydrogen evolution reaction）activity is greater than the catalytic hydrogenation reaction.（4）The dendritic Cu material was synthesized in one step on a carbon paper（CP）and graphene oxide（GO）substrate by using the chronoamperometry method,and the dendritic Cu/GO/CP composite catalytic material was successfully prepared in only120s.The dendritic Cu/GO/CP composite catalyst prepared by this method has a larger specific capacitance（0.75 m F/cm²）and better electrochemical properties.It is used in the research of electrocatalytic nitrogen reduction to synthesize ammonia in 0.1 M KOH electrolyte system.When the electrolysis voltage is-0.10 V vs RHE,the ammonia yield of the dendritic Cu/GO/CP copper-based composite material reaches 17.27 ug·h-1·cm^-2,and the Faraday efficiency is 9.76%.（5）After many repeated experiments and long-term operation,it shows that the dendritic Cu/GO/CP composite material has good stability for the electrocatalytic reduction of nitrogen under optimized experimental conditions.