Barite/TiO2 composite particle (B/TCP) was prepared by coating TiO2 on the surfaces of barite particles through mechano-chemical method. The preparation parameters and pigment properties of B/TCP as well as the intera...Barite/TiO2 composite particle (B/TCP) was prepared by coating TiO2 on the surfaces of barite particles through mechano-chemical method. The preparation parameters and pigment properties of B/TCP as well as the interaction mechanism between barite and TiO2 were studied. The results indicated that the mechanical co-grinding process and the proportion of TiO2 affected the properties of B/TCP significantly. B/TCP prepared under optimal conditions was similar to TiO2 in pigment properties. It was mainly the strong electrostatic attraction between barite and TiO2 in water that combined them firmly and then formed B/TCP.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
Nanocrystalline TiO 2 has been studied extensively in recent years as photocatalysts to deal with environmental pollutions, such as water purification, wastewater treatment and air purification. Here a novel sonochemi...Nanocrystalline TiO 2 has been studied extensively in recent years as photocatalysts to deal with environmental pollutions, such as water purification, wastewater treatment and air purification. Here a novel sonochemical method for directly preparing anatase nanocrystalline TiO 2 has been established. Nanocrystalline TiO 2 were synthesized by the hydrolysis of titanium tetrabutyl in the presence of water and ethanol under a high intensity ultrasonic irradiation(20 kHz, 100 W/cm 2) at 363 K for 3 h. The structure and particle sizes of the product were dependent upon the reaction temperature, the acidity of the medium and the reaction time. Characterization was accomplished by using various different techniques, such as powder X ray diffraction(XRD), transmission electron microscopy(TEM), thermogravimetry differential thermal analysis(TG DTA) and Fourier transform infrared(FTIR) spectroscopy. The TEM images showed that the particles of TiO 2 were columnar in shape and the average sizes were ca. 3 nm×7 nm . The formation mechanism of nanocrystalline TiO 2 under a high intensity ultrasonic irradiation was also investigated. The hydrolytic species of titanium tetrabutyl in water condensed to form a large number of tiny gel nuclei which aggregated to form larger clusters. Ultrasound irradiation generated a lot of local hot spots within the gel and the crystal structural unit was formed near the hot spots with the decrease of the gel nuclei, which lead to form nanocrystal particles.展开更多
基金National Key Technology R&D Program of China (2008BAE60B06)Beijing Municipal Science & Technology Commission (Z080003032208015)
文摘Barite/TiO2 composite particle (B/TCP) was prepared by coating TiO2 on the surfaces of barite particles through mechano-chemical method. The preparation parameters and pigment properties of B/TCP as well as the interaction mechanism between barite and TiO2 were studied. The results indicated that the mechanical co-grinding process and the proportion of TiO2 affected the properties of B/TCP significantly. B/TCP prepared under optimal conditions was similar to TiO2 in pigment properties. It was mainly the strong electrostatic attraction between barite and TiO2 in water that combined them firmly and then formed B/TCP.
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 ).
文摘Nanocrystalline TiO 2 has been studied extensively in recent years as photocatalysts to deal with environmental pollutions, such as water purification, wastewater treatment and air purification. Here a novel sonochemical method for directly preparing anatase nanocrystalline TiO 2 has been established. Nanocrystalline TiO 2 were synthesized by the hydrolysis of titanium tetrabutyl in the presence of water and ethanol under a high intensity ultrasonic irradiation(20 kHz, 100 W/cm 2) at 363 K for 3 h. The structure and particle sizes of the product were dependent upon the reaction temperature, the acidity of the medium and the reaction time. Characterization was accomplished by using various different techniques, such as powder X ray diffraction(XRD), transmission electron microscopy(TEM), thermogravimetry differential thermal analysis(TG DTA) and Fourier transform infrared(FTIR) spectroscopy. The TEM images showed that the particles of TiO 2 were columnar in shape and the average sizes were ca. 3 nm×7 nm . The formation mechanism of nanocrystalline TiO 2 under a high intensity ultrasonic irradiation was also investigated. The hydrolytic species of titanium tetrabutyl in water condensed to form a large number of tiny gel nuclei which aggregated to form larger clusters. Ultrasound irradiation generated a lot of local hot spots within the gel and the crystal structural unit was formed near the hot spots with the decrease of the gel nuclei, which lead to form nanocrystal particles.
