The electrocarboxylation reaction is an attractive means to convert CO_(2) into valuable chemicals under ambient conditions,while it still suffers from low efficiency due to the high stability of CO_(2).In this work,w...The electrocarboxylation reaction is an attractive means to convert CO_(2) into valuable chemicals under ambient conditions,while it still suffers from low efficiency due to the high stability of CO_(2).In this work,we report a double activation strategy for simultaneously activating CO_(2) and acetophenone by silver-doped CeO_(2)(Ag-CeO_(2)) nanowires,featuring as an effective electrocatalyst for electrocarboxylation of acetophenone with CO_(2).Compared to the Ag foil,Ag nanoparticles and CeO_(2) nanowires,the Ag-CeO_(2)nanowire catalyst allowed to reduce the onset potential difference between CO_(2) and acetophenone activation,thus enabling efficient electrocarboxylation to form 2-phenyllactic acid.The Faradaic efficiency for producing 2-phenyllactic acid reached 91%at−1.8 V versus Ag/AgI.This double activation strategy of activating both CO_(2)and organic substrate molecules can benefit the catalyst design to improve activities and selectivities in upgrading CO_(2)fixation for higher-value electrocarboxylation.展开更多
为更有效脱除空气中甲醛污染物,分别将CeO_2、MnO_x-CeO_2和Ag/MnO_x-CeO_2催化剂与介质阻挡放电等离子体结合,在大气压及35℃下脱除空气中甲醛,选取脱除效果最好的Ag/MnO_xCeO_2为催化剂,研究放电电压和HCHO初始体积分数以及空速对HCH...为更有效脱除空气中甲醛污染物,分别将CeO_2、MnO_x-CeO_2和Ag/MnO_x-CeO_2催化剂与介质阻挡放电等离子体结合,在大气压及35℃下脱除空气中甲醛,选取脱除效果最好的Ag/MnO_xCeO_2为催化剂,研究放电电压和HCHO初始体积分数以及空速对HCHO脱除率的影响。结果表明,当空气中甲醛的体积分数为2.0×10-4、水的体积分数为1.0%、空速为16 364 h-1、放电电压为18 k V时,Ag/MnO_x-CeO_2与等离子体结合的甲醛脱除率达99.0%,高出单纯等离子体和单纯Ag/MnO_x-CeO_2催化氧化(不放电)脱除率之和23.9%。实验证明,在脱除空气中HCHO的过程中,Ag/MnO_x-CeO_2与等离子体结合产生了很强的协同作用,且等离子体中的活性物种是协同作用的关键。展开更多
The synthesis of ultrafine cerium dioxide precursor via homogeneous precipitation was studied. Mixed aqueous solution of anhydrous cerium nitrate and urea was first heated to 85℃ for 2 h, and the prepared suspension ...The synthesis of ultrafine cerium dioxide precursor via homogeneous precipitation was studied. Mixed aqueous solution of anhydrous cerium nitrate and urea was first heated to 85℃ for 2 h, and the prepared suspension was then aged at room temperature for various periods of time. White precipitate was finally collected by centrifuging and washed with distilled water and anhydrous ethanol. The obtained cerium dioxide (CeO2) precursor was observed with SEM. It was found that the morphology and size of the precursor were strongly affected by aging time and stirring conditions (with or without stirring). The precipitated fine spherical particles of the precursor changed their shape from ellipse to slice or directly to slice. Fine spherical monodispersed (300 nm) precursor powders could be obtained by controlling the aging time. Stirring the solution also could change the reaction process and thus the morphology and size of the precursor were changed.展开更多
文摘The electrocarboxylation reaction is an attractive means to convert CO_(2) into valuable chemicals under ambient conditions,while it still suffers from low efficiency due to the high stability of CO_(2).In this work,we report a double activation strategy for simultaneously activating CO_(2) and acetophenone by silver-doped CeO_(2)(Ag-CeO_(2)) nanowires,featuring as an effective electrocatalyst for electrocarboxylation of acetophenone with CO_(2).Compared to the Ag foil,Ag nanoparticles and CeO_(2) nanowires,the Ag-CeO_(2)nanowire catalyst allowed to reduce the onset potential difference between CO_(2) and acetophenone activation,thus enabling efficient electrocarboxylation to form 2-phenyllactic acid.The Faradaic efficiency for producing 2-phenyllactic acid reached 91%at−1.8 V versus Ag/AgI.This double activation strategy of activating both CO_(2)and organic substrate molecules can benefit the catalyst design to improve activities and selectivities in upgrading CO_(2)fixation for higher-value electrocarboxylation.
文摘为更有效脱除空气中甲醛污染物,分别将CeO_2、MnO_x-CeO_2和Ag/MnO_x-CeO_2催化剂与介质阻挡放电等离子体结合,在大气压及35℃下脱除空气中甲醛,选取脱除效果最好的Ag/MnO_xCeO_2为催化剂,研究放电电压和HCHO初始体积分数以及空速对HCHO脱除率的影响。结果表明,当空气中甲醛的体积分数为2.0×10-4、水的体积分数为1.0%、空速为16 364 h-1、放电电压为18 k V时,Ag/MnO_x-CeO_2与等离子体结合的甲醛脱除率达99.0%,高出单纯等离子体和单纯Ag/MnO_x-CeO_2催化氧化(不放电)脱除率之和23.9%。实验证明,在脱除空气中HCHO的过程中,Ag/MnO_x-CeO_2与等离子体结合产生了很强的协同作用,且等离子体中的活性物种是协同作用的关键。
基金National Natural Science Foundation of China(21076206)Natural Basic Research Program of China(973 Program,2010CB732302)National High Technology Research and Development Program(863 Program,2011AA050706)
基金the Natural Science Foundation of Jiangsu Province under pro ject No.BK2002010.
文摘The synthesis of ultrafine cerium dioxide precursor via homogeneous precipitation was studied. Mixed aqueous solution of anhydrous cerium nitrate and urea was first heated to 85℃ for 2 h, and the prepared suspension was then aged at room temperature for various periods of time. White precipitate was finally collected by centrifuging and washed with distilled water and anhydrous ethanol. The obtained cerium dioxide (CeO2) precursor was observed with SEM. It was found that the morphology and size of the precursor were strongly affected by aging time and stirring conditions (with or without stirring). The precipitated fine spherical particles of the precursor changed their shape from ellipse to slice or directly to slice. Fine spherical monodispersed (300 nm) precursor powders could be obtained by controlling the aging time. Stirring the solution also could change the reaction process and thus the morphology and size of the precursor were changed.
