摘要
与传统的合成氨工艺(Haber-Bosch法)相比,电催化还原硝酸盐合成氨技术具有可再生能源驱动、反应条件温和及无二次污染等优势。然而,该反应仍面临催化剂催化活性不足、产物选择性较低以及稳定性较差等挑战。采用水热法合成了不同铜铝比例(n(Cu)/n(Al)=x=1.5、2或3)的铜铝水滑石(Cu_(x)Al-LDH),并对其进行了表征分析与电化学性能测试,系统探讨了铜铝比例、电解液中初始NO_(3)^(-)-N质量浓度、施加电位及光照条件对电催化还原硝酸盐合成氨的影响。结果表明,在电位为-0.6 V vs.RHE及初始NO_(3)^(-)-N质量浓度为500 mg/L条件下,Cu_(2)Al-LDH电极的法拉第效率达到98.2%,氨产率达到822.3μg/(h·cm^(2))。增加光照后,在相同条件下,Cu_(1.5)Al-LDH电极表现出更优的催化性能,理论法拉第效率达到150.5%,氨产率达到1149.1μg/(h·cm^(2))。此外,Cu_(2)Al-LDH和Cu_(1.5)Al-LDH电极分别在电催化和光辅助电催化条件下表现出优异的稳定性,持续反应10 h后仍能维持较高的法拉第效率。铜铝水滑石在电催化还原硝酸盐合成氨反应中表现出优异性能,具有应用于绿色合成氨的潜力。
Compared with the traditional ammonia synthesis process(Haber Bosch method),electrocatalytic nitrate reduction to ammonia offers advantages such as renewable energy input,mild reaction conditions and no secondary pollution.However,this reaction still faces challenges including insufficient catalytic activity,low product selectivity and poor stability.Copper-aluminum layered double hydroxides(Cu_(x)Al-LDH)with different ratios of Cu to Al(n(Cu)/n(Al)=x=1.5,2 or 3)were synthesized by hydrothermal method.Their structures were characterized,and their electrochemical performances were evaluated.The effects of Cu/Al ratio,initial NO_(3)^(-)-N mass concentration in the electrolyte,applied potential and illumination on the efficiency of electrocatalytic nitrate reduction to ammonia were systematically investigated.The results show that the Cu_(2)Al-LDH electrode achieves a Faradaic efficiency of 98.2%and an ammonia yield of 822.3μg/(h·cm^(2))at-0.6 V vs.RHE with an initial NO_(3)^(-)-N mass concentration of 500 mg/L.Upon light illumination,the Cu_(1.5)Al-LDH electrode exhibits enhanced catalytic performance under the same conditions,achieving a theoretical Faradaic efficiency of 150.5%and an ammonia yield of 1149.1μg/(h·cm^(2)).Furthermore,both Cu_(2)Al-LDH and Cu_(1.5)Al-LDH electrodes display excellent stability under electrocatalytic and photo-assisted electrocatalytic conditions,respectively,maintaining high Faradaic efficiency after continuous operation for ten hours.These results indicate that copper-aluminum layered double hydroxides show promising performance for the electrocatalytic reduction of nitrate to ammonia and hold great potential for green ammonia synthesis.
作者
宇文晨
张泰境
吉欢欢
YUWEN Chen;ZHANG Taijing;JI Huanhuan(College of Urban and Rural Construction,Hebei Agricultural University,Baoding 071000,Hebei,China)
出处
《低碳化学与化工》
北大核心
2025年第11期138-149,共12页
Low-Carbon Chemistry and Chemical Engineering
基金
河北农业大学引进人才科研专项(YJ201921)。
关键词
硝酸盐还原
合成氨
电催化储能
铜铝水滑石
nitrate reduction
ammonia synthesis
electrocatalytic energy storage
copper-aluminum layered double hydroxide
