http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Enhanced photocatalytic activity of Au-doped Au@ZnO core-shell flower-like nanocomposites
Jung, Hyeon Jin,Koutavarapu, Ravindranadh,Lee, Seulki,Kim, Ju Hyun,Choi, Hyun Chul,Choi, Myong Yong Elsevier 2018 JOURNAL OF ALLOYS AND COMPOUNDS Vol.735 No.-
<P><B>Abstract</B></P> <P>We introduce a simple and low-cost three-step hydrothermal and pulsed laser ablation technique for the fabrication of flower-like pure ZnO nanostructures, Au@ZnO core-shell nanocomposites, and Au@ZnO/Au core-shell nanocomposites doped with various concentrations (5, 10, and 15 wt%) of Au nanoparticles without using surfactants or catalysts to enhance the catalytic performance of ZnO under UV–visible irradiation. The decoration of Au nanoparticles on the surface of ZnO promoted the absorption of visible light due to the surface plasmon resonance of Au. Further, we evaluated the photocatalytic performance of the nanocomposites in the degradation of methylene blue (MB). Our findings revealed that the Au@ZnO/Au core-shell nanocomposites with 5 wt% of doped Au NPs demonstrated the highest photocatalytic activity. In addition, radical-scavenging experiments were conducted to determine the main reactive species formed in the reaction mixture, and accordingly, a plausible photocatalytic reaction mechanism for the enhanced photodegradation of MB is presented.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Hydrothermal and pulsed laser ablation methods were used for photocatalysts. </LI> <LI> Pure ZnO, Au@ZnO and Au@ZnO/Au nanocomposites (NCs) were synthesized. </LI> <LI> The dopant Au NPs promotes the visible absorption in Au@ZnO/Au NCs. </LI> <LI> Au@ZnO/Au NCs showed enhanced photocatalytic activity for MB. </LI> <LI> Au@ZnO/Au NCs with 5 wt% of Au NP dopants showed the best photocatalytic activity. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
바부바출라,V.V.N. Harish,Ravindranadh Koutavarapu,심재술,유기수 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.76 No.-
We report a novel fabrication method for CdS nanorods (NRs) @ SnO2 quantum dots (SQDs) core–shell NR(CdS@SnO2 core–shell NR) heterojunction photocatalysts using a simple two-step process involvinghydrothermal and ultrasonication techniques. The surface of the fabricated CdS NRs was completelydecorated with colloidal SQDs. The amount of colloidal SQDs on the surface of the CdS NRs was optimizedto achieve the maximum degradation efficiency. The superior performance of these NRs in dyedegradation was attributed to the synergetic effect of the colloidal SQDs, which protected the surface ofthe CdS NRs.
Lee, Seung Jun,Jung, Hyeon Jin,Koutavarapu, Ravindranadh,Lee, Seung Heon,Arumugam, Malathi,Kim, Ju Hyun,Choi, Myong Yong Elsevier BV * North-Holland 2019 Applied Surface Science Vol.496 No.-
<P><B>Abstract</B></P> <P>Recently, photocatalysis has attracted great attention due to its potential applications in the environmental sector. Visible light driven metal–semiconductor photocatalysts with efficient light absorption, high charge separation, enhanced surface plasmon resonance, and utilized active sites have emerged as promising materials for the degradation of organic pollutants. Here, plasmonic ZnO/Au/Pd nanocomposites, with various concentrations of Au (5, 10, and 15 wt%) and 5 wt% of Pd nanoparticles (NPs) were prepared by a facile and eco–friendly three–step pulsed laser ablation in liquid and photodeposition technique without utilizing any surfactants or capping agents to enhance the photocatalytic performance under visible light illumination. The plasmonic properties of Au NPs and an excellent trapping of photogenerated electrons on the surface of Pd led to the improved photocatalytic activity (PCA). The as-prepared ZnO/Au/Pd nanocomposites were characterized by numerous spectroscopic and microscopic techniques, and the results confirmed the fabrication of Au and Pd NPs homogeneously decorated on the surface of ZnO nanospheres. The effect of plasmon improved photocatalytic activity of the ZnO/Au/Pd photocatalysts was investigated by the degradation of methylene blue dye under visible light illumination. The optimum ZnO/Au/Pd nanocomposite was ca. 5.4 times more efficient at degrading methylene blue than pure ZnO. This exceptional improvement of photocatalytic activity for the ZnO/Au/Pd catalysts was due to the enhanced surface plasmon resonance effect of the Au NPs under visible light illumination, and the deposited Pd NPs assisted as an electron storage chamber for the degradation of methylene blue, thus, enabling the separation of charge carriers. Based on the experimental results, a possible photocatalytic mechanism for the degradation of methylene blue catalyzed by the ZnO/Au/Pd nanocomposite was proposed.</P> <P><B>Highlights</B></P> <P> <UL> <LI> ZnO/Au/Pd catalyst prepared by pulsed laser ablation and photodeposition technique. </LI> <LI> Facile and eco-friendly technique without utilizing surfactants or capping agents. </LI> <LI> Plasmon improved photocatalytic performance of the ZnO/Au/Pd photocatalysts. </LI> <LI> Photocatalytic degradation of methylene blue under visible light illumination. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Babu, Bathula,Harish, V.V.N.,Koutavarapu, Ravindranadh,Shim, Jaesool,Yoo, Kisoo Elsevier 2019 Journal of industrial and engineering chemistry Vol.76 No.-
<P><B>Abstract</B></P> <P>We report a novel fabrication method for CdS nanorods (NRs) @ SnO<SUB>2</SUB> quantum dots (SQDs) core–shell NR (CdS@SnO<SUB>2</SUB> core–shell NR) heterojunction photocatalysts using a simple two-step process involving hydrothermal and ultrasonication techniques. The surface of the fabricated CdS NRs was completely decorated with colloidal SQDs. The amount of colloidal SQDs on the surface of the CdS NRs was optimized to achieve the maximum degradation efficiency. The superior performance of these NRs in dye degradation was attributed to the synergetic effect of the colloidal SQDs, which protected the surface of the CdS NRs.</P> <P><B>Highlights</B></P> <P> <UL> <LI> 1D core–shell nanorods were fabricated via a sonochemical approach. </LI> <LI> CdS nanorods were coated with colloidal SQDs, and the SQD quantity was optimized. </LI> <LI> CdS@SnO<SUB>2</SUB> core–shell NRs exhibited highly efficient and stable catalytic activity. </LI> <LI> Degradation efficiency of C–S 1.0 was ∼6.8 times higher than that of bare CdS NRs. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Je, Mingyu,Jung, Hyeon Jin,Koutavarapu, Ravindranadh,Lee, Seung Jun,Lee, Seung Heon,Kim, Sung Kuk,Choi, Hyun Chul,Choi, Myong Yong Elsevier 2018 Materials chemistry and physics Vol.217 No.-
<P><B>Abstract</B></P> <P><B>Hypothesis</B></P> <P>Semiconductor nanocrystals with response in the near-infrared region include lead chalcogenide quantum dots (QDs), and these materials show a strong quantum confinement effect due to their large Bohr radius compared with the group II–VI QDs. In the present study, a facile synthesis of lead selenide (PbSe) QDs using a pulsed laser irradiation in liquid (PLIL) is presented.</P> <P><B>Experiments</B></P> <P>PbSe QDs were produced using a pulsed Nd:YAG laser (532 nm, 10 Hz, 7 ns) irradiation of the Pb and Se mixed precursor solutions using the following three surfactants at various concentrations: cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulfate (SDS), and polyvinylpyrrolidone (PVP).</P> <P><B>Findings</B></P> <P>Interestingly, it was observed that the synthesis and particle size of PbSe QDs obtained via the PLIL technique were strongly influenced by the type and concentration of the surfactants and by the varying wavelength and power of the laser. A secondary irradiation of the prepared sample in PVP solution resulted in the formation of rock salt crystalline PbSe QDs that were approximately 6.83 nm in size.</P> <P><B>Highlights</B></P> <P> <UL> <LI> PbSe QDs are prepared from Pb and Se salts by a PLIL technique. </LI> <LI> The formation of PbSe QDs are dependent on surfactants. </LI> <LI> Structural and morphology studies confirm the formation of PbSe QDs. </LI> <LI> CTAB is effective for the synthesis of PbSe QDs at various experimental conditions. </LI> <LI> PVP is effective for the formation of small PbSe QDs. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>