Highly efficient and green ammonia production is an important demand for modern agriculture.In this study,a two-step ammonia production method is developed using a gliding arc discharge in combination with Cu/Cu_(2)O ...Highly efficient and green ammonia production is an important demand for modern agriculture.In this study,a two-step ammonia production method is developed using a gliding arc discharge in combination with Cu/Cu_(2)O electrocatalysis.In this method,NO_(x)is provided by the gliding arc discharge and then electrolyzed by Cu/Cu_(2)O after alkaline absorption.The electrical characteristics,the optical characteristics and the NO_(x)production are investigated in discharges at different input voltage and the gas flow.The dependence of ammonia production through Cu/Cu_(2)O electrocatalysis on pH value and reduction potential are determined by colorimetric method.In our study,two discharge modes are observed.At high input voltage and low gas flow,the discharge is operated with a stable plasma channel which is called the steady arc gliding discharge mode(A-G mode).As lowering input voltage and raising gas flow,the plasma channel is destroyed and high frequency breakdown occurs instead,which is known as the breakdown gliding discharge mode(B-G mode).The optimal NO_(x)production of 7.34 mmol h^(-1)is obtained in the transition stage of the two discharge modes.The ammonia yield reaches0.402 mmol h^(-1)cm^(-2)at pH value of 12.7 and reduction potential of-1.0 V versus reversible hydrogen electrode(RHE).展开更多
H_(2)O吸附引起的二次电子发射增强是导致真空微波器件与设备异常放电的关键因素。为了研究H_(2)O吸附对金属表面二次电子发射特性的影响规律,该文考虑电子−H_(2)O分子碰撞的7种散射类型,采用Monte Carlo方法模拟电子−H_(2)O吸附分子的...H_(2)O吸附引起的二次电子发射增强是导致真空微波器件与设备异常放电的关键因素。为了研究H_(2)O吸附对金属表面二次电子发射特性的影响规律,该文考虑电子−H_(2)O分子碰撞的7种散射类型,采用Monte Carlo方法模拟电子−H_(2)O吸附分子的散射过程,同时考虑功函数变化对电子出射概率的影响,建立了一种H_(2)O吸附Cu表面的二次电子发射模型,统计二次电子的最终状态,并对二次电子发射系数(secondary electron yield,SEY)和二次电子能谱(secondary electron spectrum,SES)的变化规律进行分析。结果表明,H_(2)O吸附能够降低表面功函数,且产生更多电离电子,导致SEY增大;但当吸附厚度大于100 nm时,SEY不再继续增大,这是由于吸附层较厚时,电子无法进入Cu基底,仅在吸附层内散射。SES的谱峰随着吸附厚度的增加而增强,表明H_(2)O能够促使更多的低能电子出射,这是造成二次电子发射增强的重要因素。该文的模型为研究复杂表面状态的二次电子发射提供了可靠的分析方法,相关结果能够用于分析解释真空微波器件与设备放电形成机理,优化设备部件的设计参数。展开更多
Cuprous oxide (Cu 2O) was prepared by reducing Cu 2+ with NaBH 4. 4-chloro-nitrobenzene was used to examined for the photocatalyst in the artificial solar. The results indicate cuprous oxide has high photoactivity and...Cuprous oxide (Cu 2O) was prepared by reducing Cu 2+ with NaBH 4. 4-chloro-nitrobenzene was used to examined for the photocatalyst in the artificial solar. The results indicate cuprous oxide has high photoactivity and the organic degradation was completed. Under the irradiation of visible light, 4-chloro-nitrobenzene solution of 10 mg·1 -1and 40.0 mg·1 -1 decomposed 95% and 84% in 60 minutes, respectively. The degradation is first order reaction.展开更多
A novel coprecipitation-reduction process has been proposed for preparing highly selective Cu/ZnO/Al 2O 3 catalysts for methanol synthesis from CO 2 hydrogenation. Compared to the catalysts prepared by the conventiona...A novel coprecipitation-reduction process has been proposed for preparing highly selective Cu/ZnO/Al 2O 3 catalysts for methanol synthesis from CO 2 hydrogenation. Compared to the catalysts prepared by the conventional method, the new catalysts prepared via the new method exhibit much higher BET surface area and pore size, much smaller crystallite size and higher catalytic activity and selectivity in CO 2 hydrogenation to methanol. It is also found that the molar ratio of Cu + to Cu 0 on the surface of the catalyst obtained by coprecipitation-reduction is much higher than that on the reduced catalyst obtained by the conventional method, which could be crucial for its high activity and selectivity for catalytic hydrogenation of CO 2 to methanol.展开更多
以硝酸铜为前驱体,不采用任何模板,通过逐步水热法合成了花状Cu2O/Cu复合纳米材料.用扫描电镜(SEM)、X射线衍射(XRD)和紫外-可见漫反射光谱(DRS)对样品进行表征.结果表明,花状纳米Cu2O/Cu材料是由长为300-500nm,宽为30-70nm的带状花瓣构...以硝酸铜为前驱体,不采用任何模板,通过逐步水热法合成了花状Cu2O/Cu复合纳米材料.用扫描电镜(SEM)、X射线衍射(XRD)和紫外-可见漫反射光谱(DRS)对样品进行表征.结果表明,花状纳米Cu2O/Cu材料是由长为300-500nm,宽为30-70nm的带状花瓣构成,在可见光区域有很强的吸收.复合材料中Cu的含量可以通过反应时间进行调控.对染料Procion Red MX-5B(PR)的可见光催化降解,Cu能明显提高Cu2O的光催化性能.当Cu质量分数为27%-71%时,复合材料Cu2O/Cu的催化活性明显高于单相Cu2O.与立方体形貌的Cu2O/Cu复合材料相比,花状纳米Cu2O/Cu复合材料对染料PR有更高的催化降解性能.且该复合材料有较高的循环回收利用率.展开更多
文摘Highly efficient and green ammonia production is an important demand for modern agriculture.In this study,a two-step ammonia production method is developed using a gliding arc discharge in combination with Cu/Cu_(2)O electrocatalysis.In this method,NO_(x)is provided by the gliding arc discharge and then electrolyzed by Cu/Cu_(2)O after alkaline absorption.The electrical characteristics,the optical characteristics and the NO_(x)production are investigated in discharges at different input voltage and the gas flow.The dependence of ammonia production through Cu/Cu_(2)O electrocatalysis on pH value and reduction potential are determined by colorimetric method.In our study,two discharge modes are observed.At high input voltage and low gas flow,the discharge is operated with a stable plasma channel which is called the steady arc gliding discharge mode(A-G mode).As lowering input voltage and raising gas flow,the plasma channel is destroyed and high frequency breakdown occurs instead,which is known as the breakdown gliding discharge mode(B-G mode).The optimal NO_(x)production of 7.34 mmol h^(-1)is obtained in the transition stage of the two discharge modes.The ammonia yield reaches0.402 mmol h^(-1)cm^(-2)at pH value of 12.7 and reduction potential of-1.0 V versus reversible hydrogen electrode(RHE).
文摘H_(2)O吸附引起的二次电子发射增强是导致真空微波器件与设备异常放电的关键因素。为了研究H_(2)O吸附对金属表面二次电子发射特性的影响规律,该文考虑电子−H_(2)O分子碰撞的7种散射类型,采用Monte Carlo方法模拟电子−H_(2)O吸附分子的散射过程,同时考虑功函数变化对电子出射概率的影响,建立了一种H_(2)O吸附Cu表面的二次电子发射模型,统计二次电子的最终状态,并对二次电子发射系数(secondary electron yield,SEY)和二次电子能谱(secondary electron spectrum,SES)的变化规律进行分析。结果表明,H_(2)O吸附能够降低表面功函数,且产生更多电离电子,导致SEY增大;但当吸附厚度大于100 nm时,SEY不再继续增大,这是由于吸附层较厚时,电子无法进入Cu基底,仅在吸附层内散射。SES的谱峰随着吸附厚度的增加而增强,表明H_(2)O能够促使更多的低能电子出射,这是造成二次电子发射增强的重要因素。该文的模型为研究复杂表面状态的二次电子发射提供了可靠的分析方法,相关结果能够用于分析解释真空微波器件与设备放电形成机理,优化设备部件的设计参数。
文摘Cuprous oxide (Cu 2O) was prepared by reducing Cu 2+ with NaBH 4. 4-chloro-nitrobenzene was used to examined for the photocatalyst in the artificial solar. The results indicate cuprous oxide has high photoactivity and the organic degradation was completed. Under the irradiation of visible light, 4-chloro-nitrobenzene solution of 10 mg·1 -1and 40.0 mg·1 -1 decomposed 95% and 84% in 60 minutes, respectively. The degradation is first order reaction.
文摘A novel coprecipitation-reduction process has been proposed for preparing highly selective Cu/ZnO/Al 2O 3 catalysts for methanol synthesis from CO 2 hydrogenation. Compared to the catalysts prepared by the conventional method, the new catalysts prepared via the new method exhibit much higher BET surface area and pore size, much smaller crystallite size and higher catalytic activity and selectivity in CO 2 hydrogenation to methanol. It is also found that the molar ratio of Cu + to Cu 0 on the surface of the catalyst obtained by coprecipitation-reduction is much higher than that on the reduced catalyst obtained by the conventional method, which could be crucial for its high activity and selectivity for catalytic hydrogenation of CO 2 to methanol.
文摘以硝酸铜为前驱体,不采用任何模板,通过逐步水热法合成了花状Cu2O/Cu复合纳米材料.用扫描电镜(SEM)、X射线衍射(XRD)和紫外-可见漫反射光谱(DRS)对样品进行表征.结果表明,花状纳米Cu2O/Cu材料是由长为300-500nm,宽为30-70nm的带状花瓣构成,在可见光区域有很强的吸收.复合材料中Cu的含量可以通过反应时间进行调控.对染料Procion Red MX-5B(PR)的可见光催化降解,Cu能明显提高Cu2O的光催化性能.当Cu质量分数为27%-71%时,复合材料Cu2O/Cu的催化活性明显高于单相Cu2O.与立方体形貌的Cu2O/Cu复合材料相比,花状纳米Cu2O/Cu复合材料对染料PR有更高的催化降解性能.且该复合材料有较高的循环回收利用率.
