稳定化缺电子Cu^(δ+)活性点位电催化还原水体硝氮  

Electrocatalytic reduction of nitrate at the stabilized electron-deficient Cu^(δ+) active sites

作　　者：蒋光明[1] 欧阳嘉亿 李逍雨 刘子旬 吕晓书 姜岩[1] 赵钰鑫[1] 董帆 Guangming Jiang;Jiayi Ouyang;Xiaoyu Li;Zixun Liu;Xiaoshu Lü;Yan Jiang;Yuxin Zhao;Fan Dong(Enginering Research Center for Waste Oil Recovery Technology and Equipment,Ministry of Education,Chongqing Technology and Business University,Chongqing 400067,China;Research Center for Environmental and Energy Catalysis,Institute of Fundamental and Frontier Sciences,Universiy of Electronic Seience and Technology of China,Chengdu 611731,China)

机构地区：[1]重庆工商大学,废油资源化技术与装备教育部工程研究中心,重庆40067 [2]电子科技大学基础与前沿研究院,环境与能源催化研究中心,成都611731

出　　处：《科学通报》2022年第25期3054-3063,共10页Chinese Science Bulletin

基　　金：国家重点研发计划(2020YFA0710000);国家自然科学基金(22176019,22176029,51978110,21822601);重庆市基础研究与前沿探索面上项目(cstc2019jcyj-msxm X0260);重庆市教委科学技术项目(KJQN201800829,KJQN201900837,KJZD-K202000802)资助。

摘　　要：电催化还原水体硝氮(electrocatalytic nitrate reduction reaction,ENRR)是极具应用潜力的绿色脱氮技术.铜基催化剂因活性高而受研究者青睐,缺电子Cu^(δ+)是其中主要活性位,但在ENRR较负工作电压下难稳定(转化为Cu^(0)).本文以市售Cu(OH)_(2)颗粒为前驱体,通过在其表面修饰1,4-萘二甲酸分子(1,4-NDC)并原位电还原活化,成功构建Cu^(δ+)-1,4-NDC催化活性点位(Cu(OH)_(2)/1,4-NDC-AT);因1,4-NDC羧基上氧的高电负性和化学稳定性,Cu^(δ+)在ENRR过程中能稳定存在.脱氮性能测试结果表明,Cu(OH)_(2)/1,4-NDC-AT在-0.40 V vs.RHE(可逆氢电极)下处理NO_(3)^(-)-N废水(22.5 mg/L),产物中NH_(3)-N选择性大于90%,比表面活性和质量活性可达1034.7 mg N/(h m^(2))和89.1 mg N/(h g_(Cu)),是相应Cu(OH)_(2)-AT的2.3和5.1倍,亦优于大部分同类催化剂.优化1,4-NDC用量和工作电压可进一步提升质量活性,在n_(1,4-NDC)/n(Cu(OH)_(2))=2.16和-0.50 V时质量活性分别提升至147.1和104.6 mg N/(h g_(Cu)).针对低浓度NO3_(3)^(-)-N废水,本文提出“ENRR+NH_(3)-N吸附去除”耦合技术,彻底消除水中氮物种;针对高浓度NO_(3)^(-)-N废水,提出“ENRR+NH_(3)-N回收”耦合技术,将水中氮以(NH_(4))_(2)SO_(4)形式回收(回收率约98.0%).With the extensive use of nitrogen fertilizers,sewage discharges and industrial processes that consume nitric acid,the exposure level of nitrate(NO_(3)^(-)-N)in environmental water bodies has significantly increased in the past decades.The NO_(3)^(-)anion has a stable chemical structure,and is hardly removed by natrual self-cleaning.It has adverse effect,and is primarily responsible for the eutrophication in lakes as well as some physiological diseases in neighboring mammal inhabitants,such as the methemoglobinemia.Strict regulations on the maximum contaminant level of 10 mg/L for NO_(3)^(-)-N in the drinking water has then been set by the World Health Organization,the United States Environmental Protection Agency and the China Environmental Protection Administration.To minimize the adverse effects of NO_(3)^(-)-N,various technologies,including ion exchange,electrolysis,biological denitrification,and catalytic reduction by H_(2)or Fe^(0),have then been developed to eliminate the NO_(3)^(-)-N from water.Among them,electrocatalytic reduction of nitrate(ENRR),driven by the renewable electric energy,is receiving increasing research interests,due to its substantial nitrate removal capacity,mild reaction conditions and minimal daily maintenances.Copper-based materials are favored as the ENRR catalysts by researchers because of their high activity,chemical stability and low cost.The electron-deficient Cu^(δ+)is the main active site at the catalyst surface,but it is readily to be reduced to Cu^(0)at the very negative ENRR potentials,leading to the performance deterioration during the long-term reaction process.In this paper,we reported a facile approach to construct the Cu^(δ+)-1,4-naphthalene dicarboxylic acid(1,4-NDC)catalytic active sites through the surface decoration of the Cu(OH)_(2)particles with the 1,4-NDC molecule at room temperature,followed by an in-situ electrochemical activation process under a negative potential of-0.40 V vs.RHE(reversible hydrogen electrode,the same below)(the product is denoted as Cu(O

关 键 词：硝态氮 电催化还原 铜 缺电子状态 氨氮回收 

分 类 号：X703[环境科学与工程—环境工程]