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耦合氨氧化和水还原反应实现电化学共合成硝酸盐和氢气
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作者 朱可涵 蒋海凤 +3 位作者 陈高锋 吴昊 丁良鑫 王海辉 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2023年第12期216-226,共11页
硝酸(HNO_(3))是一种重要的含氮化学品,在肥料、火药及炸药等制造领域有广泛的应用,全球年产量高达5000万公吨.传统的硝酸生产主要通过Ostwald工艺,该工艺需要高温(600-800°C)和高压(4-10 bar)条件,并使用贵金属催化剂(如Pt-Rh合金... 硝酸(HNO_(3))是一种重要的含氮化学品,在肥料、火药及炸药等制造领域有广泛的应用,全球年产量高达5000万公吨.传统的硝酸生产主要通过Ostwald工艺,该工艺需要高温(600-800°C)和高压(4-10 bar)条件,并使用贵金属催化剂(如Pt-Rh合金网),先通过逐步催化氧化Haber-Bosch法制得氨,再进一步生成硝酸和水.该方法能耗高,对化石燃料依赖性强,且会排放温室气体CO_(2).因此,探索在温和条件下高效、环保和可持续地制备硝酸方法具有重要意义.本文设计了一种新型的电化学氨氧化和水还原反应耦合体系,可同时电化学合成硝酸盐和氢气.通过电化学氧化方法原位实现了Cu原子和O原子的可控重组,在不同条件下合成出以Cu_(2)O为主的Cu-OX-PBS催化剂和以Cu O为主的Cu-OX-KOH纳米片阵列催化剂.对比两种催化剂催化氨氧化反应性能发现,CuO是将氨转化为NO_(3)^(–)的主要活性位点.在使用Cu-OX-KOH催化剂进行氨氧化反应时,通过调控氨氧化电位策略可实现八电子转移过程中氨到NO_(3)^(–)的转化.Cu-OX-KOH纳米片阵列催化剂在1.5 Vvs.RHE下合成NOx–的法拉第效率高达98.7%,并且最高产率达到121.0±5.4μmol h^(-1)cm^(-2)(2.1 V vs.RHE);同时,在阴极端连续产生H2时具有97.7%的法拉第效率(1.8 V vs.RHE),从而实现了硝酸盐和氢气的同时高效合成.此外,在经108 h稳定性测试后,该反应体系可收集到0.2 molL–1NOx–产物,且反应后催化剂形貌未发生改变,表明CuO纳米片阵列催化剂具有较高的稳定性和实际应用潜力.通过监测反应体系中NH_(3),NO_(2)^(–),NO_(3)^(–)三种物质随时间的变化情况,考察了氨氧化电合成NO_(3)^(–)的反应过程.结果表明,NO_(2)^(–)是氨氧化到NO_(3)^(–)反应过程中的重要中间体,并且随着反应进行,NO_(2)^(–)最终转化为NO_(3)^(–).为进一步分析反应机理,利用原位红外技术检测重要中间体*NH_(2),*NH,*NO和NO_(2)等的形成,并通过密度泛函理论验证了在CuO催化作用下氨氧化到NO_(3)^(–)是一个逐级脱氢加氧的过程,进而推测出氨氧化到NO_(3)^(–)的八电子反应路径并分析了实验过程中NO_(2)^(–)中间体生成的可能原因.综上所述,本文将氨氧化与电解水巧妙地耦合电化学共合成硝酸盐和氢气,为在温和条件下利用可再生能源实现氨与水共活化及高效转化提供了新思路,并为现场原位生成硝酸和氢气提供了参考. 展开更多
关键词 氨氧化 CuO纳米片阵列 硝酸电合成 水还原 产氢
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Yiguanjian decoction enhances fetal liver stem/progenitor cell-mediated repair of liver cirrhosis through regulation of macrophage activation state 被引量:11
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作者 Ying Xu Wei-Wei Fan +7 位作者 Wen Xu Shi-Li Jiang gao-feng chen cheng Liu Jia-Mei chen Hua Zhang Ping Liu Yong-Ping Mu 《World Journal of Gastroenterology》 SCIE CAS 2018年第42期4759-4772,共14页
AIM To investigate whether Yiguanjian decoction(YGJ) has an anti-liver cirrhotic effect and whether it regulates hepatic stem cell differentiation.METHODS A rat model of liver cirrhosis was established via subcutaneou... AIM To investigate whether Yiguanjian decoction(YGJ) has an anti-liver cirrhotic effect and whether it regulates hepatic stem cell differentiation.METHODS A rat model of liver cirrhosis was established via subcutaneous injection of carbon tetrachloride(CCl4) for8 wk. From the beginning of the ninth week, the rats received 2-acetylaminofluorene(2-AAF) by oral gavage and a DLK-1+ fetal liver stem/progenitor cell(FLSPC)transplant or an FLSPC transplant in combination with YGJ treatment for 4 wk. In vitro, lipopolysaccharide(LPS)-activated macrophages were co-cultured with WB-F344 cells, and the differentiation of WB-F344 cells was observed in the presence and absence of YGJ treatment.RESULTS FLSPC transplantation improved liver function and histopathology, and inhibited the activation of the noncanonical Wnt signaling pathway, while activating the canonical Wnt signaling pathway. YGJ enhanced the therapeutic effects of FLSPCs and also promoted the liver regeneration differentiation of FLSPCs into hepatocytes.In vitro, LPS-activated macrophages promoted the differentiation of WB-F344 cells into myofibroblasts, and the canonical Wnt signaling was inhibited while the noncanonical Wnt signaling was activated in WB-F344 cells.YGJ suppressed the activation of macrophages and then inhibited non-canonical Wnt signaling and promoted canonical Wnt signaling.CONCLUSION YGJ enhances FLSPC-mediated repair of liver cirrhosis through regulation of macrophage activation state, and YGJ in combination with stem cell transplantation may be a suitable treatment for end-stage liver cirrhosis. 展开更多
关键词 CIRRHOSIS Hepatic PROGENITOR cells Wnt signaling pathway MACROPHAGE 2-acetylaminofluorene Carbon TETRACHLORIDE Yiguanjian DECOCTION
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Efficient ammonia electrosynthesis from nitrate via a three-step relay mechanism
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作者 Haifeng Jiang gao-feng chen Haihui Wang 《Science China Chemistry》 SCIE EI CSCD 2024年第1期319-320,共2页
Electrocatalytically converting nitrate waste to value-added ammonia(NO3−RR)is beneficial to environmental restoration and an attractive candidate for green ammonia production[1].However,developing NO_(3)^(-)RR in an ... Electrocatalytically converting nitrate waste to value-added ammonia(NO3−RR)is beneficial to environmental restoration and an attractive candidate for green ammonia production[1].However,developing NO_(3)^(-)RR in an energy-saving way remains a significant challenge due to the slow kinetics inherent in multi-step electron and proton transfer,making previous investigations for NO_(3)^(-)RR generally operate at a large overpotential(<-0.2 V versus reversible hydrogen electrode(RHE))to achieve optimal efficiency and industrial current for NH3 synthesis[2]. 展开更多
关键词 AMMONIA NITRATE KINETICS
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