Bismuth sulfide(Bi_(2)S_(3))with an earth-abundant elemental composition has attracted wide attention as a promising n-type thermoelectric material in recent years.However,the thermoelectric performance of Bi_(2)S_(3)...Bismuth sulfide(Bi_(2)S_(3))with an earth-abundant elemental composition has attracted wide attention as a promising n-type thermoelectric material in recent years.However,the thermoelectric performance of Bi_(2)S_(3) is limited by its low electrical conductivity.It is therefore vital to choose an effective dopant for enhancing the electrical transport properties of Bi_(2)S_(3).In this work,by using the solid-state reaction and the spark plasma sintering technique,Bi_(2)S_(3) bulk materials doped with x mol%LaCl_(3)(x=0,1.0,2.0,3.0)were successfully fabricated.The conductivity of Bi_(2)S_(3) samples doped with 2 mol%LaCl_(3)(about 153 S cm^(-1))was one order of magnitude higher than that of the pristine Bi_(2)S_(3) sample,resulting in a high power factor of 483μW m-1 K-2 at 625 K.The lattice thermal conductivity of the doped samples decreased due to more grain boundaries,point defects and nano-precipitates.Consequently,a peak thermoelectric figure-of-merit(ZT)of 0.50 at 625 K was obtained for the Bi_(2)S_(3) sample with 2 mol%LaCl_(3) doping,which was over four times higher compared to that of pristine Bi_(2)S_(3)(about 0.11 at 625 K).The results suggest that the dopant LaCl_(3) is effective for modifying carrier concentration and reducing lattice thermal conductivity.展开更多
CeO_(2),La_(2)O_(3),and CeO_(2)-Y_(2)O_(3) oxides were coated on the surface of spherical granular AI_(2)O_(3)(3-5 mm)through impregnation method,and proved as better supports of Pd and Pt catalysts.The influences of ...CeO_(2),La_(2)O_(3),and CeO_(2)-Y_(2)O_(3) oxides were coated on the surface of spherical granular AI_(2)O_(3)(3-5 mm)through impregnation method,and proved as better supports of Pd and Pt catalysts.The influences of rare earth metal doping on the adsorption rates of Pd and Pt ions,as well as the catalytic performance,were investigated.Results show that the H_(2)PtCl_(6)·6H_(2)O adsorption rates of the Al_(2)O_(3) carriers modified by Ce,La,and CeY increase significantly.These rare earth coatings can adsorb almost all H2PtCl_(6)·6H_(2)O in the solution.Compared with Pt/Al_(2)O_(3) catalyst,Pt/Ce-AI_(2)O_(3) and Pt/CeY-AI_(2)O_(3) catalysts have better degradation performance for toluene,and the T_(90) temperatures are both about 147℃.According to X-ray photoelectron spectroscopy(XPS)characterization,Pt^(0)is an important active species for catalytic oxidation reaction of toluene.After CeO_(2)modification to the conventional Pt/Al_(2)O_(3)catalyst,the proportion of Pt^(0)increases from 74.5%to 82.1%.When the Pt^(0)content in the metal state is improved,the redox activity of the catalyst is promoted correspondingly.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.11764025 and 51702150)supported by the Science,Technology,and Innovation Commission of Shenzhen Municipality(Grant No.KQCX2015033110182370 and JCYJ20150831142508365).
文摘Bismuth sulfide(Bi_(2)S_(3))with an earth-abundant elemental composition has attracted wide attention as a promising n-type thermoelectric material in recent years.However,the thermoelectric performance of Bi_(2)S_(3) is limited by its low electrical conductivity.It is therefore vital to choose an effective dopant for enhancing the electrical transport properties of Bi_(2)S_(3).In this work,by using the solid-state reaction and the spark plasma sintering technique,Bi_(2)S_(3) bulk materials doped with x mol%LaCl_(3)(x=0,1.0,2.0,3.0)were successfully fabricated.The conductivity of Bi_(2)S_(3) samples doped with 2 mol%LaCl_(3)(about 153 S cm^(-1))was one order of magnitude higher than that of the pristine Bi_(2)S_(3) sample,resulting in a high power factor of 483μW m-1 K-2 at 625 K.The lattice thermal conductivity of the doped samples decreased due to more grain boundaries,point defects and nano-precipitates.Consequently,a peak thermoelectric figure-of-merit(ZT)of 0.50 at 625 K was obtained for the Bi_(2)S_(3) sample with 2 mol%LaCl_(3) doping,which was over four times higher compared to that of pristine Bi_(2)S_(3)(about 0.11 at 625 K).The results suggest that the dopant LaCl_(3) is effective for modifying carrier concentration and reducing lattice thermal conductivity.
基金supported by the Scientific Research Fund of Zhejiang Provincial Education Department(Y202043197)the National Natural Science Foundation of China(22078294)+1 种基金the Natural Science Foundation of Zhejiang Province(LZ21E080001,LGF20E080018)the Key Laboratory of Environmental Pollution Control Technology Research of Zhejiang Province(2021ZEKL04)。
文摘CeO_(2),La_(2)O_(3),and CeO_(2)-Y_(2)O_(3) oxides were coated on the surface of spherical granular AI_(2)O_(3)(3-5 mm)through impregnation method,and proved as better supports of Pd and Pt catalysts.The influences of rare earth metal doping on the adsorption rates of Pd and Pt ions,as well as the catalytic performance,were investigated.Results show that the H_(2)PtCl_(6)·6H_(2)O adsorption rates of the Al_(2)O_(3) carriers modified by Ce,La,and CeY increase significantly.These rare earth coatings can adsorb almost all H2PtCl_(6)·6H_(2)O in the solution.Compared with Pt/Al_(2)O_(3) catalyst,Pt/Ce-AI_(2)O_(3) and Pt/CeY-AI_(2)O_(3) catalysts have better degradation performance for toluene,and the T_(90) temperatures are both about 147℃.According to X-ray photoelectron spectroscopy(XPS)characterization,Pt^(0)is an important active species for catalytic oxidation reaction of toluene.After CeO_(2)modification to the conventional Pt/Al_(2)O_(3)catalyst,the proportion of Pt^(0)increases from 74.5%to 82.1%.When the Pt^(0)content in the metal state is improved,the redox activity of the catalyst is promoted correspondingly.
