Self-supporting NiFe LDH-MoS_(x) integrated electrode for highly efficient water splitting at the industrial electrolysis conditions

Developing effective and practical electrocatalyst under industrial electrolysis conditions is critical for renewable hydrogen production.Herein,we report the self-supporting NiFe LDH-MoS_(x) integrated electrode for water oxidation under normal alkaline test condition(1 M KOH at 25℃)and simulated industrial electrolysis conditions(5 M KOH at 65℃).Such optimized electrode exhibits excellent oxygen evolution reaction(OER)performance with overpotential of 195 and 290 mV at current density of 100 and 400 mA·cm^(-2) under normal alkaline test condition.Notably,only over-potential of 156 and 201 mV were required to achieve the current density of 100 and 400mA·cm^(-2) under simulated industrial electrolysis conditions.No significant degradations were observed after long-term durability tests for both conditions.When using in two-electrode system,the operational voltages of 1.44 and 1.72 V were required to achieve a current density of 10 and 100 mA·cm^(-2) for the overall water splitting test(NiFe LDH-MoS_(x)/INF||20%Pt/C).Additionally,the operational voltage of employing NiFe LDH-MoS_(x)/INF as both cathode and anode merely require 1.52 V at 50mA·cm^(-2) at simulated industrial electrolysis conditions.Notably,a membrane electrode assembly(MEA)for anion exchange membrane water electrolysis(AEMWEs)using NiFe LDH-MoS_(x)/INF as an anode catalyst exhibited an energy conversion efficiency of 71.8%at current density of 400 mA·cm^(-2)in 1 M KOH at 60℃.Further experimental results reveal that sulfurized substrate not only improved the conductivity of NiFe LDH,but also regulated its electronic configurations and atomic composition,leading to the excellent activity.The easy-obtained and cost-effective integrated electrodes are expected to meet the large-scale application of industrial water electrolysis.

AC-Fe/Ni联合次氯酸钠去除水中硝酸盐氮

随着工业、农业的快速发展,硝酸盐氮(NO_(3)^(−)-N)的污染范围不断扩大、污染程度不断加深,因此,有效去除水中的NO_(3)^(−)-N具有重要意义。本研究通过在活性炭上原位负载零价铁和镍,制备了载铁/镍双金属活性炭(ACFe/Ni),并联合次氯酸钠去除水中的NO_(3)^(−)-N。结果表明,AC-Fe/Ni能够快速还原NO_(3)^(−)-N,反应20 min时NO_(3)^(−)-N的去除率为99.29%,比AC-Fe提高40%,且N2选择性提高8%。AC-Fe/Ni在酸性和碱性条件下均能有效还原NO_(3)^(−)-N,但碱性条件更有利于形成N_(2)。减少材料投加量或提高NO_(3)^(−)-N初始质量浓度均会降低NO_(3)^(−)-N的去除率;共存阴离子、阳离子、有机物对NO_(3)^(−)-N的去除无明显影响。NO_(3)^(−)-N的还原过程总铁释出量仅为0.28 mg·L^(−1),总镍浓度低于0.05 mg·L^(−1)。与此同时,次氯酸钠联用能有效去除出水中的NH_(4)^(+)-N,反应60 min时溶液中残余氨氮仅为0.28 mg·L^(−1)。