Pd/TiO2 catalysts prepared by three different methods(impregnation,deposition-precipitation,and polyethylene glycol reduction)were investigated in the selective catalytic reduction of NOx by H2(H2-SCR).It was found th...Pd/TiO2 catalysts prepared by three different methods(impregnation,deposition-precipitation,and polyethylene glycol reduction)were investigated in the selective catalytic reduction of NOx by H2(H2-SCR).It was found that the preparation method exerted a significant effect on the activity of the Pd/TiO2 catalyst,and that the catalyst prepared by the polyethylene glycol reduction method exhibited the highest activity in the reduction of NOx.Characterization of the catalyst showed that,in the Pd/TiO2 catalyst prepared by the polyethylene glycol reduction method,the existing Pd species was Pd0,which is the desirable species for the H2-SCR of NOx.In situ DRIFTS studies demonstrated that over this catalyst,more chelating nitrite and monodentate nitrite species formed,both of which are reactive intermediates in the H2-SCR of NOx.All of these factors account for the high activity of Pd/TiO2 prepared by the polyethylene glycol reduction method.展开更多
TiO2 decorated with partially crystallized Pd nanoparticles （Pd/TiO2-P） was successfully prepared by atmospheric-pressure dielectric barrier discharge cold plasma. The XRD and XPS analyses proved that Pd ions were r...TiO2 decorated with partially crystallized Pd nanoparticles （Pd/TiO2-P） was successfully prepared by atmospheric-pressure dielectric barrier discharge cold plasma. The XRD and XPS analyses proved that Pd ions were reduced to partially crystallized metallic Pd nanoparticles in Pd/TiO2-P. The XPS spectra also indicated that an enhanced metal-support interaction was formed due to the existence of partially crystallized Pd nanoparticles with lower coordination number in Pd/TiO2-P. Photocatalytic activity of Pd/TiO2-P was much higher than that of TiO2 samples decorated with well crystallized Pd nanoparticles.展开更多
In this study, palladium-loaded titania nano- tubes was fabricated on a titanium plate （Pd/TiO2NTs/Ti） for efficient electrodechlorination of 2,4-chlorophenol with a mild pH condition. The nature of PdYTiO2NTs/Ti el...In this study, palladium-loaded titania nano- tubes was fabricated on a titanium plate （Pd/TiO2NTs/Ti） for efficient electrodechlorination of 2,4-chlorophenol with a mild pH condition. The nature of PdYTiO2NTs/Ti electrodes was characterized by field-emission scanning electron microscope （FESEM）, X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS）, and cyclic voltammetry （CV） techniques. The characterization results indicated the generation of Pd~ nanoparticles which were evenly dispersed on titania nanotubes arrays on the Pd/ TiO2NTs/Ti surface. An effective degradation efficiency of up to 91% was achieved within 60 min at cathode potential of -0.7 V （vs. SCE） and initial pH of 5.5. The effects of the applied cathode potential and initial pH on the degradation efficiency were studied. A near neutral condition was more favorable since very low and very high pHs were not conducive to the dechlorination process. Furthermore, the intermediates analysis showed that the Pd/TiO2NTs/Ti electrode could completely remove chlor- ine from 2, 4-dichlorophenol since only phenol was detected as the byproduct and the concentration of released chlorine ions indicated near-complete dechlorination. This work presents a good alternative technique for eliminating persistent chlorophenols in polluted wastewater without maintaining strong acidic environment.展开更多
基金supported by the National Key R&D Program of China(2017YFC0210700)the National Natural Science Foundation of China(21876009,21611130170)+1 种基金the Beijing Municipal Natural Science Foundation(8162030)the Fundamental Research Funds for the Central Universities(XK1802-1)~~
文摘Pd/TiO2 catalysts prepared by three different methods(impregnation,deposition-precipitation,and polyethylene glycol reduction)were investigated in the selective catalytic reduction of NOx by H2(H2-SCR).It was found that the preparation method exerted a significant effect on the activity of the Pd/TiO2 catalyst,and that the catalyst prepared by the polyethylene glycol reduction method exhibited the highest activity in the reduction of NOx.Characterization of the catalyst showed that,in the Pd/TiO2 catalyst prepared by the polyethylene glycol reduction method,the existing Pd species was Pd0,which is the desirable species for the H2-SCR of NOx.In situ DRIFTS studies demonstrated that over this catalyst,more chelating nitrite and monodentate nitrite species formed,both of which are reactive intermediates in the H2-SCR of NOx.All of these factors account for the high activity of Pd/TiO2 prepared by the polyethylene glycol reduction method.
基金supported by the National Natural Science Foundation of China(21173028)the Science and Technology Research Project of Liaoning Provincial Education Department(L2013464)+1 种基金the Scientific Research Foundation for the Doctor of Liaoning Province(20131004)the Program for Liaoning Excellent Talents in University(LR2012042)
文摘TiO2 decorated with partially crystallized Pd nanoparticles （Pd/TiO2-P） was successfully prepared by atmospheric-pressure dielectric barrier discharge cold plasma. The XRD and XPS analyses proved that Pd ions were reduced to partially crystallized metallic Pd nanoparticles in Pd/TiO2-P. The XPS spectra also indicated that an enhanced metal-support interaction was formed due to the existence of partially crystallized Pd nanoparticles with lower coordination number in Pd/TiO2-P. Photocatalytic activity of Pd/TiO2-P was much higher than that of TiO2 samples decorated with well crystallized Pd nanoparticles.
文摘In this study, palladium-loaded titania nano- tubes was fabricated on a titanium plate （Pd/TiO2NTs/Ti） for efficient electrodechlorination of 2,4-chlorophenol with a mild pH condition. The nature of PdYTiO2NTs/Ti electrodes was characterized by field-emission scanning electron microscope （FESEM）, X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS）, and cyclic voltammetry （CV） techniques. The characterization results indicated the generation of Pd~ nanoparticles which were evenly dispersed on titania nanotubes arrays on the Pd/ TiO2NTs/Ti surface. An effective degradation efficiency of up to 91% was achieved within 60 min at cathode potential of -0.7 V （vs. SCE） and initial pH of 5.5. The effects of the applied cathode potential and initial pH on the degradation efficiency were studied. A near neutral condition was more favorable since very low and very high pHs were not conducive to the dechlorination process. Furthermore, the intermediates analysis showed that the Pd/TiO2NTs/Ti electrode could completely remove chlor- ine from 2, 4-dichlorophenol since only phenol was detected as the byproduct and the concentration of released chlorine ions indicated near-complete dechlorination. This work presents a good alternative technique for eliminating persistent chlorophenols in polluted wastewater without maintaining strong acidic environment.
