近日，大连理工大学李新勇教授团队在Applied Catalysis B: Environmental上发表了题为“Interfacial engineering of CoMn2O4/NC induced electronic delocalization boosts electrocatalytic nitrogen oxyanions reduction to ammonia”的研究论文（DOI: 10.1016/j.apcatb.2022.122090），探究了CoMn2O4/NC复合材料在中性条件下对硝酸盐还原反应（NO3−RR）的催化性能及反应机理，实现了硝酸盐（NO3−）到氨（NH3）的高性能转化。进一步结合系列原位谱学表征技术和密度泛函理论（DFT）计算联用的策略解析了NO3−RR的机理。最后，考察了耦合阳极醇氧化反应（BOR）对阴极产NH3活性的影响。
催化剂制备和表征
Fig. 1. (a) Illustration of the preparation of CoMn2O4/NC for electroreduction NO3− to NH3. (b) SEM, (c) TEM and (d) HR-TEM images of CoMn2O4/NC. (e) HAADF-STEM image and (f-j) the corresponding elemental mapping images of C, N, O, Co and Mn, respectively.
材料合成中，采用静电纺丝-碳化-氧化法合成CoMn2O4/NC复合催化剂。SEM和TEM结果表明材料具有多通道纤维结构，CoMn2O4和NC之间存在清晰的界面；HAADF-STEM结果表明CoMn2O4/NC上各元素均匀分散。
Fig. 2. (a) XRD pattern of CoMn2O4/NC. High-resolution XPS spectra of (b) Co 2p and (c) Mn 2p regions of CoMn2O4/NC. DOS of (d) Co 3d, (e) Mn 3d and (f) O 2p for CoMn2O4/NC.
性能测试
Fig. 3. (a) LSV curves of CoMn2O4/NC, CoMn2O4 and NC in 0.1 M Na2SO4 with and without 0.1 M NO3−. The NH3 (b) yield rate and (c) Faradaic efficiency of NO3−RR for CoMn2O4/NC, CoMn2O4 and NC at different potentials. (d) The NH3-to-NO2−product ratios for different catalysts. (e) The partial current densities of NH3 evolution for different catalysts with 0.1 M NO3−. (f) The NH3 yield rate of CoMn2O4/NC detected by UV-Vis and 1H-NMR method at −0.7 V vs. RHE.
Fig. 4. (a) LSV curves of CoMn2O4, CoMn2O4/NC and NC in 0.1 M Na2SO4 with 0.1 M NO2−. The NH3 (b) yield rate and (c) Faradaic efficiency of NO2−RR for CoMn2O4/NC, CoMn2O4 and NC at different potentials. (d) The partial current densities of NH3evolution for different catalysts with 0.1 M NO2−.
催化机理
Fig. 5. Electrochemical in situ Raman spectra of CoMn2O4/NC for (a and b) NO3−RR and (c and d) NO2−RR.Charge density difference of *NO3configuration at (e) CoMn2O4/NC and (f) CoMn2O4(Cyan and yellow regions represent negative and positive charges, respectively, with iso-surfaces energy density of 0.002 e Å−3).
Fig. 6. (a) Charge density difference of CoMn2O4/NC. (Cyan and yellow regions represent negative and positive charges, respectively, with iso-surfaces energy density of 0.0004 e Å −3.) (b) In situ DEMS measurements of CoMn2O4/NC for NO3−RR. Free energy diagram (U = 0 V and pH = 7) for NO3−RR on the substrate of (c) CoMn2O4 and (d) CoMn2O4/NC.
耦合阳极醇氧化反应
Fig. 7. (a) LSV curves of NO2−RR coupling OER and BOR in two-electrode system. (b) The energy consumption savings of NO2−RR||BOR at different current densities. (c) NH3 yield rate and Faradaic efficiency at 1.75 V for 2 h in two-electrode system. (d) The anode corresponding products yield rate and Faradaic efficiency of NO2−RR||BOR.
这项工作报道了一种CoMn2O4/NC复合电催化材料的制备方法，并基于界面诱导策略从电子层面深入剖析了该复合催化剂获得较高电催化NO3−RR产NH3活性的机理。研究通过电化学性能测试、原位谱学（产物和中间物种鉴定）和DFT计算等手段揭示了中性电解液中电催化NO3−RR产NH3的潜在路径。该工作为设计和应用新型电催化材料去除水体NO3−污染物并获得高附加值NH3提供了参考。
https://www.sciencedirect.com/science/article/pii/S0926337322010311#sec0100
声明
本文仅供科研分享，不做盈利使用，如有侵权，请联系后台小编删除
“邃瞳科学云”直播服务
“邃瞳科学云"平台正在收集、整理各类学术会议信息，欢迎学会、期刊、会议组织方择优在邃瞳平台上进行线上直播，希望藉此帮助广大科研人员跨越时空的限制，实现自由、畅通地交流互动。欢迎老师同学们提供会议信息（会有礼品赠送），学会、期刊、会议组织方商谈合作，均请联系翟女士：18612651915（微信同）。
投稿、荐稿、爆料：Editor@scisight.cn
扫描二维码下载
邃瞳科学云APP
