The paper reports the fabrication of Zn-doped TiO_2 nanotubes(Zn-TONT)/ZnO nanoflakes heterostructure for the first time,which shows improved performance as a photoanode in dye-sensitized solar cell(DSSC).The layered ...The paper reports the fabrication of Zn-doped TiO_2 nanotubes(Zn-TONT)/ZnO nanoflakes heterostructure for the first time,which shows improved performance as a photoanode in dye-sensitized solar cell(DSSC).The layered structure of this novel nanoporous structure has been analyzed unambiguously by Rutherford backscattering spectroscopy,scanning electron microscopy,and X-ray diffractometer.The cell using the heterostructure as photoanode manifests an enhancement of about an order in the magnitude of the short circuit current and a seven-fold increase in efficiency,over pure TiO_2 photoanodes.Characterizations further reveal that the Zn-TONT is preferentially oriented in [001] direction and there is a Ti metal-depleted interface layer which leads to better band alignment in DSSC.展开更多
Zn-doped TiO2 (Zn?TiO2) thin films were prepared by the sol?gel method on titanium substrates with heat treatment at different temperatures. The effects of heat treatment temperatures and Zn doping on the structure, p...Zn-doped TiO2 (Zn?TiO2) thin films were prepared by the sol?gel method on titanium substrates with heat treatment at different temperatures. The effects of heat treatment temperatures and Zn doping on the structure, photocathodic protection and photoelectrochemical properties of TiO2 thin films were investigated. It is indicated that the photoelectrical performance of the Zn?TiO2 films is enhanced with the addition of Zn element compared with the pure-TiO2 film and the largest decline by 897 mV in the electrode potential is achieved under 300 °C heat treatment. SEM?EDS analyses show that Zn element is unevenly distributed in Zn?TiO2 films; XRD patterns reveal that the grain size of Zn?TiO2 is smaller than that of pure-TiO2; FTIR results indicate that Zn - O bond forms on Zn?TiO2 surface. Ultraviolet visible absorption spectra prove that Zn?TiO2 shifts to visible light region.Mott?Shottky curves show that the flat-band potential of Zn?TiO2 is more negative and charge carrier density is bigger than that ofpure-TiO2, implying that under the synergy of the width of the space-charge layer, carrier density and flat-band potential, Zn?TiO2 with 300 °C heat treatment displays the best photocathodic protection performance.展开更多
The electronic structures and optical properties of intrinsic β-Ga2O3 and Zn-dopedβ-Ga2O3 are investigated by first-principles calculations. The analysis about the thermal stability shows that Zn-doped β-Ga2O3 rema...The electronic structures and optical properties of intrinsic β-Ga2O3 and Zn-dopedβ-Ga2O3 are investigated by first-principles calculations. The analysis about the thermal stability shows that Zn-doped β-Ga2O3 remains stable. The Zn doping does not change the basic electronic structure of β-Ga2O3, but only generates an empty energy level above the maximum of the valence band, which is shallow enough to make the Zn-doped β-Ga2O3 a typical p-type semiconductor. Because of Zn doping, absorption and reflectivity are enhanced in the near infrared region. The higher absorption and reflectivity of ZnGa（2） than those of ZnGa（1） are due to more empty energy states of ZnGa（2） than those of ZnGa（1） near Ef in the near infrared region.展开更多
Synergistic interplays involving multiple active centers originating from TiO2 nanotube layers(TNT)and ruthenium(Ru)species comprising of both single atoms(SAs)and nanoparticles(NPs)augment the alkaline hydrogen evolu...Synergistic interplays involving multiple active centers originating from TiO2 nanotube layers(TNT)and ruthenium(Ru)species comprising of both single atoms(SAs)and nanoparticles(NPs)augment the alkaline hydrogen evolution reaction(HER)by enhancing Volmer kinetics from rapid water dissociation and improving Tafel kinetics from efficient H*desorption.Atomic layer deposition of Ru with 50 process cycles results in a mixture of Ru SAs and 2.8-0.4 nm NPs present on TNT layers,and it emerges with the highest HER activity among all the electrodes synthesized.A detailed study of the Ti and Ru species using different high-resolution techniques confirmed the presence of Ti^(3+)states and the coexistence of Ru SAs and NPs.With insights from literature,the role of Ti^(3+),appropriate work functions of TNT layers and Ru,and the synergistic effect of Ru SAs and Ru NPs in improving the performance of alkaline HER were elaborated and justified.The aforementioned characteristics led to a remarkable performance by having 9mV onset potentials and 33 mV dec^(-1) of Tafel slopes and a higher turnover frequency of 1.72 H2 s^(-1) at 30 mV.Besides,a notable stability from 28 h staircase chronopotentiometric measurements for TNT@Ru surpasses TNT@Pt in comparison.展开更多
We prepared TiO 2(anatase) and Sn doped TiO 2 nanoparticlate film by Plasma enhanced Chemical Vapor Deposition(PECVD) method. XRD and XPS experiments showed that Sn was doped into the lattice of TiO 2 with a ratio of ...We prepared TiO 2(anatase) and Sn doped TiO 2 nanoparticlate film by Plasma enhanced Chemical Vapor Deposition(PECVD) method. XRD and XPS experiments showed that Sn was doped into the lattice of TiO 2 with a ratio of n (Sn)∶ n (Ti)=1∶10 . Sn doping largely enhanced the photocatalytic activity of TiO 2 film for phenol degradation. The enhancement in photoactivity by doping was discussed, based on the characterization with AFM, FTIR and EFISPS. Sn doping produced localized level of Sn 4+ in the band gap of TiO 2, about 0.4 eV below the conduction band, which could capture photogenerated electrons and reduce O 2 adsorbed on the surface of TiO 2 film, thus accelerated the photocatalytic reaction.展开更多
The transition metal ion doped TiO 2 nanoparticles were prepared with hydrothermal method, and the effects of doping different metal ions on the ability of TiO 2 in photocatalyzing degradation of rhodamine B(RB) were ...The transition metal ion doped TiO 2 nanoparticles were prepared with hydrothermal method, and the effects of doping different metal ions on the ability of TiO 2 in photocatalyzing degradation of rhodamine B(RB) were studied. The results showed that the doping of Fe 3+ , Co 2+ , Ni 2+ and Cr 3+ in TiO 2 nanoparticles made the photocatalytic efficiency of the TiO 2 particles reduce and the higher the initial content of Fe 3+ , the lower the ability of TiO 2 in photocatalyzing the degradation of RB. But the doping of Zn 2+ and Cd 2+ , especially Zn 2+ , made the photocatalytic efficiency of the TiO 2 particles enhance, showing a great increase of the rate constant( k ) and the initial reaction rate( r ini ).展开更多
基金UGC-DAE CSR,Indore,for funding through a collaborative project and SAIF IIT Bombay for the help with SEMsupported by the Michigan Space Grant Consortium+1 种基金by Hope CollegeDAE-BRNS for funding the preliminary works
文摘The paper reports the fabrication of Zn-doped TiO_2 nanotubes(Zn-TONT)/ZnO nanoflakes heterostructure for the first time,which shows improved performance as a photoanode in dye-sensitized solar cell(DSSC).The layered structure of this novel nanoporous structure has been analyzed unambiguously by Rutherford backscattering spectroscopy,scanning electron microscopy,and X-ray diffractometer.The cell using the heterostructure as photoanode manifests an enhancement of about an order in the magnitude of the short circuit current and a seven-fold increase in efficiency,over pure TiO_2 photoanodes.Characterizations further reveal that the Zn-TONT is preferentially oriented in [001] direction and there is a Ti metal-depleted interface layer which leads to better band alignment in DSSC.
基金Project(cstc2011jj A50008)supported by the Natural Science Foundation of Chongqing,ChinaProject(14ZB0025)supported by Education Department of Sichuan Province,China
文摘Zn-doped TiO2 (Zn?TiO2) thin films were prepared by the sol?gel method on titanium substrates with heat treatment at different temperatures. The effects of heat treatment temperatures and Zn doping on the structure, photocathodic protection and photoelectrochemical properties of TiO2 thin films were investigated. It is indicated that the photoelectrical performance of the Zn?TiO2 films is enhanced with the addition of Zn element compared with the pure-TiO2 film and the largest decline by 897 mV in the electrode potential is achieved under 300 °C heat treatment. SEM?EDS analyses show that Zn element is unevenly distributed in Zn?TiO2 films; XRD patterns reveal that the grain size of Zn?TiO2 is smaller than that of pure-TiO2; FTIR results indicate that Zn - O bond forms on Zn?TiO2 surface. Ultraviolet visible absorption spectra prove that Zn?TiO2 shifts to visible light region.Mott?Shottky curves show that the flat-band potential of Zn?TiO2 is more negative and charge carrier density is bigger than that ofpure-TiO2, implying that under the synergy of the width of the space-charge layer, carrier density and flat-band potential, Zn?TiO2 with 300 °C heat treatment displays the best photocathodic protection performance.
基金Project supported by the National Natural Science Foundation of China(Grant No.10974077)the Natural Science Foundation of Shandong Province,China(Grant No.2009ZRB01702)the Shandong Provincial Higher Educational Science and Technology Program,China(Grant No.J10LA08)
文摘The electronic structures and optical properties of intrinsic β-Ga2O3 and Zn-dopedβ-Ga2O3 are investigated by first-principles calculations. The analysis about the thermal stability shows that Zn-doped β-Ga2O3 remains stable. The Zn doping does not change the basic electronic structure of β-Ga2O3, but only generates an empty energy level above the maximum of the valence band, which is shallow enough to make the Zn-doped β-Ga2O3 a typical p-type semiconductor. Because of Zn doping, absorption and reflectivity are enhanced in the near infrared region. The higher absorption and reflectivity of ZnGa（2） than those of ZnGa（1） are due to more empty energy states of ZnGa（2） than those of ZnGa（1） near Ef in the near infrared region.
基金support from the European Union Horizon 2020 program(project HERMES,nr.952184)the Ministry of Education,Youth and Sports of the Czech Republic for supporting CEMNAT(LM2023037)+1 种基金Czech-NanoLab(LM2023051)infrastructures for providing ALD,SEM,EDX,XPS,TEM,and XRDCzech Science Foundation(project 23-08019X,EXPRO).
文摘Synergistic interplays involving multiple active centers originating from TiO2 nanotube layers(TNT)and ruthenium(Ru)species comprising of both single atoms(SAs)and nanoparticles(NPs)augment the alkaline hydrogen evolution reaction(HER)by enhancing Volmer kinetics from rapid water dissociation and improving Tafel kinetics from efficient H*desorption.Atomic layer deposition of Ru with 50 process cycles results in a mixture of Ru SAs and 2.8-0.4 nm NPs present on TNT layers,and it emerges with the highest HER activity among all the electrodes synthesized.A detailed study of the Ti and Ru species using different high-resolution techniques confirmed the presence of Ti^(3+)states and the coexistence of Ru SAs and NPs.With insights from literature,the role of Ti^(3+),appropriate work functions of TNT layers and Ru,and the synergistic effect of Ru SAs and Ru NPs in improving the performance of alkaline HER were elaborated and justified.The aforementioned characteristics led to a remarkable performance by having 9mV onset potentials and 33 mV dec^(-1) of Tafel slopes and a higher turnover frequency of 1.72 H2 s^(-1) at 30 mV.Besides,a notable stability from 28 h staircase chronopotentiometric measurements for TNT@Ru surpasses TNT@Pt in comparison.
文摘We prepared TiO 2(anatase) and Sn doped TiO 2 nanoparticlate film by Plasma enhanced Chemical Vapor Deposition(PECVD) method. XRD and XPS experiments showed that Sn was doped into the lattice of TiO 2 with a ratio of n (Sn)∶ n (Ti)=1∶10 . Sn doping largely enhanced the photocatalytic activity of TiO 2 film for phenol degradation. The enhancement in photoactivity by doping was discussed, based on the characterization with AFM, FTIR and EFISPS. Sn doping produced localized level of Sn 4+ in the band gap of TiO 2, about 0.4 eV below the conduction band, which could capture photogenerated electrons and reduce O 2 adsorbed on the surface of TiO 2 film, thus accelerated the photocatalytic reaction.
文摘The transition metal ion doped TiO 2 nanoparticles were prepared with hydrothermal method, and the effects of doping different metal ions on the ability of TiO 2 in photocatalyzing degradation of rhodamine B(RB) were studied. The results showed that the doping of Fe 3+ , Co 2+ , Ni 2+ and Cr 3+ in TiO 2 nanoparticles made the photocatalytic efficiency of the TiO 2 particles reduce and the higher the initial content of Fe 3+ , the lower the ability of TiO 2 in photocatalyzing the degradation of RB. But the doping of Zn 2+ and Cd 2+ , especially Zn 2+ , made the photocatalytic efficiency of the TiO 2 particles enhance, showing a great increase of the rate constant( k ) and the initial reaction rate( r ini ).
