In this study,Ni catalysts supported on Pr-doped Ce O_(2) are studied for the CO_(2) methanation reaction and the effect of Pr doping on the physicochemical properties and the catalytic performance is thoroughly evalu...In this study,Ni catalysts supported on Pr-doped Ce O_(2) are studied for the CO_(2) methanation reaction and the effect of Pr doping on the physicochemical properties and the catalytic performance is thoroughly evaluated.It is shown,that Pr^(3+)ions can substitute Ce^(4+)ones in the support lattice,thereby introducing a high population of oxygen vacancies,which act as active sites for CO_(2) chemisorption.Pr doping can also act to reduce the crystallite size of metallic Ni,thus promoting the active metal dispersion.Catalytic performance evaluation evidences the promoting effect of low Pr loadings(5 at%and 10 at%)towards a higher catalytic activity and lower CO_(2) activation energy.On the other hand,higher Pr contents negate the positive effects on the catalytic activity by decreasing the oxygen vacancy population,thereby creating a volcano-type trend towards an optimum amount of aliovalent substitution.展开更多
Undoped and praseodymium-doped zinc oxide （Pr-doped ZnO） （with 2.0-mol%-6.0-mol% Pr） nanoparticles as sunlight-driven photocatalysts are synthesized by means of co-precipitation with nitrates followed by thermal a...Undoped and praseodymium-doped zinc oxide （Pr-doped ZnO） （with 2.0-mol%-6.0-mol% Pr） nanoparticles as sunlight-driven photocatalysts are synthesized by means of co-precipitation with nitrates followed by thermal annealing. The structure, morphology, and chemical bonding of the photocatalysts are studied by x-ray diffraction （XRD）, scanning electron microscopy （SEM） with energy dispersive x-ray emission spectroscopy （EDS）, x-ray photoelectron spectroscopy （XPS）, and Fourier transform infrared spectroscopy （FTIR）, respectively. The optical properties are studied by photolu- minescence （PL） and UV-vis diffuse reflectance spectroscopy （UV-vis DRS）. We find that Pr doping does not change the crystallinity of ZnO; but it reduces the bandgap slightly, and restrains the recombination of the photogenerated electron-hole pairs. The photocatalytic performance of the photocatalysts is investigated by the photodegradation reaction of 10-mg/L rhodamine B （RhB） solution under simulated sunlight irradiation, showing a degradation rate of 93.75% in ZnO doped with 6.0-mo1% Pr.展开更多
The Pr and Ta separately doped FTO（10 at.% F incorporated Sn O2） films are fabricated via spray pyrolysis. The microstructural, topographic, optical, and electrical features of fluorine-doped TO（FTO） films are inv...The Pr and Ta separately doped FTO（10 at.% F incorporated Sn O2） films are fabricated via spray pyrolysis. The microstructural, topographic, optical, and electrical features of fluorine-doped TO（FTO） films are investigated as functions of Pr and Ta dopant concentrations. The x-ray diffraction（XRD） measurements reveal that all deposited films show polycrystalline tin oxide crystal property. FTO film has（200） preferential orientation, but this orientation changes to（211） direction with Pr and Ta doping ratio increasing. Atomic force microscopy（AFM） and scanning electron microscopy（SEM） analyses show that all films have uniform and homogenous nanoparticle distributions. Furthermore, morphologies of the films depend on the ratio between Pr and Ta dopants. From ultraviolet-visible（UV-Vis） spectrophotometer measurements, it is shown that the transmittance value of FTO film decreases with Pr and Ta doping elements increasing. The band gap value of FTO film increases only at 1 at.% Ta doping level, it drops off with Pr and Ta doping ratio increasing at other doped FTO films. The electrical measurements indicate that the sheet resistance value of FTO film initially decreases with Pr and Ta doping ratio decreasing and then it increases with Pr and Ta doping ratio increasing. The highest value of figure of merit is obtained for 1 at.% Ta- and Pr-doped FTO film. These results suggest that Pr- and Ta-doped FTO films may be appealing candidates for TCO applications.展开更多
Nanocubes derived from pure In2O3 and xPr-In2O3 (x= 1, 2, 3 and 5 mol.%) were synthesized using a facile hydrothermal method, followed by calcination. The morphological and structural characterization demonstrated tha...Nanocubes derived from pure In2O3 and xPr-In2O3 (x= 1, 2, 3 and 5 mol.%) were synthesized using a facile hydrothermal method, followed by calcination. The morphological and structural characterization demonstrated that as-synthesized samples presented regular cubes that decreased in size with the increase of the Pr doping. The data showed that the sensing performances of sensors based on In203 were notably improved after the Pr doping. Among them, the sensor based on 2 mol.% Pr-In2O3 had the best sensing performance towards the triethylamine (TEA) gas, including a high response (RaIRg = 260 to 100 ppm TEA gas, which is about 12 times higher than that of the sensor based on pure In2O3), a short response time (2s), and a low detection limit (0.2 ppm) at 350℃. The mechanism responsible for the enhancement of sensing performance was attributed to the improvement of the vacancy content of 2 mol.% Pr-ln203, which promoted the oxidation—reduction reaction with the TEA gas that occurred on the materials surface.展开更多
基金support of this work by the project“Development of new innovative low carbon energy technologies to improve excellence in the Region of Western Macedonia”(MIS 5047197)which is implemented under the Action“Reinforcement of the Research and Innovation Infrastructure”funded by the Operational Program“Competitiveness,Entrepreneurship and Innovation”(NSRF 2014-2020)co-financed by Greece and the European Union(European Regional Development Fund)。
文摘In this study,Ni catalysts supported on Pr-doped Ce O_(2) are studied for the CO_(2) methanation reaction and the effect of Pr doping on the physicochemical properties and the catalytic performance is thoroughly evaluated.It is shown,that Pr^(3+)ions can substitute Ce^(4+)ones in the support lattice,thereby introducing a high population of oxygen vacancies,which act as active sites for CO_(2) chemisorption.Pr doping can also act to reduce the crystallite size of metallic Ni,thus promoting the active metal dispersion.Catalytic performance evaluation evidences the promoting effect of low Pr loadings(5 at%and 10 at%)towards a higher catalytic activity and lower CO_(2) activation energy.On the other hand,higher Pr contents negate the positive effects on the catalytic activity by decreasing the oxygen vacancy population,thereby creating a volcano-type trend towards an optimum amount of aliovalent substitution.
基金Project supported by the International Cooperation Program of the Ministry of Science and Technology of China(Grant No.2015DFR00720)the Cooperation Program of Wuhan Science and Technology Bureau,China(Grant No.2016030409020219)the Shenzhen Committee on Science and Technology Innovation,China(Grant No.JCYJ20170818112901473)
文摘Undoped and praseodymium-doped zinc oxide （Pr-doped ZnO） （with 2.0-mol%-6.0-mol% Pr） nanoparticles as sunlight-driven photocatalysts are synthesized by means of co-precipitation with nitrates followed by thermal annealing. The structure, morphology, and chemical bonding of the photocatalysts are studied by x-ray diffraction （XRD）, scanning electron microscopy （SEM） with energy dispersive x-ray emission spectroscopy （EDS）, x-ray photoelectron spectroscopy （XPS）, and Fourier transform infrared spectroscopy （FTIR）, respectively. The optical properties are studied by photolu- minescence （PL） and UV-vis diffuse reflectance spectroscopy （UV-vis DRS）. We find that Pr doping does not change the crystallinity of ZnO; but it reduces the bandgap slightly, and restrains the recombination of the photogenerated electron-hole pairs. The photocatalytic performance of the photocatalysts is investigated by the photodegradation reaction of 10-mg/L rhodamine B （RhB） solution under simulated sunlight irradiation, showing a degradation rate of 93.75% in ZnO doped with 6.0-mo1% Pr.
文摘The Pr and Ta separately doped FTO（10 at.% F incorporated Sn O2） films are fabricated via spray pyrolysis. The microstructural, topographic, optical, and electrical features of fluorine-doped TO（FTO） films are investigated as functions of Pr and Ta dopant concentrations. The x-ray diffraction（XRD） measurements reveal that all deposited films show polycrystalline tin oxide crystal property. FTO film has（200） preferential orientation, but this orientation changes to（211） direction with Pr and Ta doping ratio increasing. Atomic force microscopy（AFM） and scanning electron microscopy（SEM） analyses show that all films have uniform and homogenous nanoparticle distributions. Furthermore, morphologies of the films depend on the ratio between Pr and Ta dopants. From ultraviolet-visible（UV-Vis） spectrophotometer measurements, it is shown that the transmittance value of FTO film decreases with Pr and Ta doping elements increasing. The band gap value of FTO film increases only at 1 at.% Ta doping level, it drops off with Pr and Ta doping ratio increasing at other doped FTO films. The electrical measurements indicate that the sheet resistance value of FTO film initially decreases with Pr and Ta doping ratio decreasing and then it increases with Pr and Ta doping ratio increasing. The highest value of figure of merit is obtained for 1 at.% Ta- and Pr-doped FTO film. These results suggest that Pr- and Ta-doped FTO films may be appealing candidates for TCO applications.
基金the National Natural Science Foundation of China (Grant No. 21471120)the International Cooperation Project of Hubei Province (2012IHA00201)+1 种基金the Educational Commission of Hubei Province of China (T201306)the Graduate Innovative Fund of Wuhan Institute of Technology (CX2018152).
文摘Nanocubes derived from pure In2O3 and xPr-In2O3 (x= 1, 2, 3 and 5 mol.%) were synthesized using a facile hydrothermal method, followed by calcination. The morphological and structural characterization demonstrated that as-synthesized samples presented regular cubes that decreased in size with the increase of the Pr doping. The data showed that the sensing performances of sensors based on In203 were notably improved after the Pr doping. Among them, the sensor based on 2 mol.% Pr-In2O3 had the best sensing performance towards the triethylamine (TEA) gas, including a high response (RaIRg = 260 to 100 ppm TEA gas, which is about 12 times higher than that of the sensor based on pure In2O3), a short response time (2s), and a low detection limit (0.2 ppm) at 350℃. The mechanism responsible for the enhancement of sensing performance was attributed to the improvement of the vacancy content of 2 mol.% Pr-ln203, which promoted the oxidation—reduction reaction with the TEA gas that occurred on the materials surface.
