• Title, Summary, Keyword: $Bi_2S_3$

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Occurrence and Mineral Chemistry of Pb-Ag-Bi-S System Minerals in the Nakdong As-Bi Deposits, South Korea (낙동 비소-비스무스 광상의 Pb-Ag-Bi-S계 광물의 산출양상과 화학조성)

  • Shin, Dong-Bok
    • Economic and Environmental Geology
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    • v.39 no.6
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    • pp.643-651
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    • 2006
  • The Pb-Ag-Bi-S system minerals such as galena-matildite solid solutions, cosalite and heyrovskyite occur in the Nakdong As-Bi deposits. Galena-matildite solid solutions commonly coexisting with native bismuth fill in microfractures of pyrite grains and form irregular shapes. Cosalite forms composite grains including native bismuth, heyrovskyite and Bi-Te-S system minerals in the matrix of quartz vein. Matildite from the Nakdong deposits has an end member composition, $Ag_{1.07-1.11}Bi_{1.12-1.20}S_2$, and an excess concentration of $0.3{\sim}2.4$ mole % $Bi_2S_3$ compared to the stoichiomeoic value. PbS concentrations in $PbS-AgBiS_2$ solid solutions do not exceed 54 mole %. The average chemical composition of cosalite in the study area is $Pb_{1.79}Bi_{2.29}Ag_{0.12}S_5$. Pb is slightly depleted compared to the ideal composition, but the concentrations of Ag and Cu reach as much as 1.47 wt.% and 0.27 wt.%, respectively. Heyrovskyite has the chemical formula of $Pb_{5.01}Ag_{0.26}Bi_{2.70}S_9$ suggesting that there occurs the coupled substitution of $2Bi^{3+}$ for $3Pb^{2+}$ as well as that of $Ag^++Bi^{3+}$ for $2Pb^{2+}$. The genetic condition of Pb-Ag-Bi-S system minerals can be confined to the temperature of $220{\sim}270^{\circ}C$ and the pressure below 200 bars.

Luminescence of CaS:Bi

  • 김창홍;편종홍;최 한;김성진
    • Bulletin of the Korean Chemical Society
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    • v.20 no.3
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    • pp.337-340
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    • 1999
  • Luminescence of bismuth activated CaS, CaS:Bi, prepared in sodium polysulfide is studied. Excitation spectrum of CaS:Bi shows a band at 350 nm due to the recombination process between holes in Na+Ca2+ and electrons in conduction bands, in addition to bands at 260 nm from band gap of CaS, and at 320 nm (1S0→1P1) and at 420 nm (1S0→3P1) from electronic energy transitions of Bi. Emission band at 450 nm is from 3P1→1S0 transition of Bi3+, bands at 500 nm and 580 nm correspond to recombinations of electron donors (Bi3+Ca2+ and VS2-) with acceptors (VCa2+ and Na+Ca2+). Emission band of 3P1→1S0 transition is shifted to longer wavelength from CaS:Bi to BaS:Bi, due to the increase of the Stokes shift by the decrease of the crystal field parameter from CaS:Bi to BaS:Bi.

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Optical Properties of $Bi_2S_3$ Thin films ($Bi_2S_3$ 薄膜의 光學的 特性)

  • Wee, Sung-Dong
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.26 no.4
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    • pp.62-66
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    • 1989
  • $Bi_2S_3$ polycrystalline and $Bi_2S_3$ amorphous thin tilm were grown by the evaporation method. The measured lattic parameters were $a=1.708{\AA},\;b=0.351{\AA},\;and\;C=3.943{\AA}$ at substrate temperature $210^{cric}C$ were shown to have the orthorhombic structure. The energy gape of $Bi_2S_3$ polycrystalline that was made from thin film were measured to be 1.375eV at $289^{cric}K.$ The optical band gap of $Bi_2S_3$ amorphous thin film was measured to be 1.71eV at $289^{cric}K.$ It was supposed to mechanism that a photon absorption was changed at the center of 674nm (1.84eV)

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Novel Bi2S3/TiO2 Heterogeneous Catalyst: Photocatalytic Mechanism for Decolorization of Texbrite Dye and Evaluation of Oxygen Species

  • Zhu, Lei;Oh, Won-Chun
    • Journal of the Korean Ceramic Society
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    • v.53 no.1
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    • pp.56-62
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    • 2016
  • A heterogeneous $Bi_2S_3/TiO_2$ composite catalyst was synthesized via a green ultrasonic-assisted method and characterized by XRD, SEM, EDX, TEM analysis. The results clearly show that the $TiO_2$ particles were homogenously coated with $Bi_2S_3$ particles, indicating that $Bi_2S_3$ particle agglomeration was effectively inhibited after the introduction of anatase $TiO_2$. The Texbrite BA-L (TBA) degradation rate constant for $Bi_2S_3/TiO_2$ composites reached $8.27{\times}10^{-3}min^{-1}$ under visible light, much higher than the corresponding value of $1.04{\times}10^{-3}min^{-1}$ for $TiO_2$. The quantities of generated hydroxyl radicals can be analyzed by DPCI degradation, which shows that under visible light irradiation, more electron-hole pairs can be generated. Finally, the possible mechanism for the generation of reactive oxygen species under visible-light irradiation was proposed as well. Our result shows the significant potential of $Bi_2S_3$-semiconductor-based $TiO_2$ hybrid materials as catalysts under visible light for the degradation of industry dye effluent substances.

The Precipitation of Second Phases by Annealing Heat Treatment in the $(Bi,Pb)_2$${Sr_2}{Ca_2}{Cu_3}{O_{10}}$ Superconductor System (BSCCO계 초전도체에서 서냉 열처리에 의한 2차상 석출)

  • 이상희;김철진;유재무
    • Journal of the Korean Ceramic Society
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    • v.37 no.12
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    • pp.1212-1220
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    • 2000
  • Bi-2223 초전도체계에서 석출물을 flux-pinning center로 이용할 수 있는지 가능성을 타진하기 위하여 $Bi_{1.8}$P $b_{0.4}$S $r_{2}$C $a_{2.2}$C $u_3$ $O_{8}$ 조성을 가진 Bi-2223/Ag 선재를 반응온도, 산소분압, 시간 등을 변화시키면서 열처리를 행하였다. 열처리 후 석출물들은 XRD, SEM, TEM, EDS로 분석하였다. Bi-2223 모상내의 (Ca, Sr)$_2$(Pb,Bi) $O_4$, B $i_{0.5}$ P $b_3$S $r_2$C $a_2$Cu $O_{12+}$$\delta$/ (3221)와 같은 2차상들의 크기와 분포는 2223 입자들의 연결성을 파괴하지 않고 열처리 조건에 의해서 조절할 수 있었다. 서냉 열처리가 된 시편은 임계전류밀도( $J_{c}$)값이 증가하였는데, 이는 2223 입자내 나노미터 크기로 형성된 석출물들이 flux-pinning sites로 작용한 것으로 추정된다.다.

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Ionic Doping Effect in Bi-layered Perovskite SrBi2Nb2O9 Ferroelectrics (비스무스 층구조형 페로브스카이트 SrBi2Nb2O9 강유전체의 이온 치환 효과)

  • Park, S.E.;Cho, J.A.;Song, T.K.;Kim, M.H.;Kim, S.S.;Lee, H.S.
    • Korean Journal of Materials Research
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    • v.13 no.12
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    • pp.846-849
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    • 2003
  • Doping effect of various ions in Bi-layered ferroelectric $SrBi_2$$Nb_2$$O_{9}$ (SBN) ceramics was studied. Undoped SBN ceramic and SBN ceramics doped with $Ba^{2+}$, $Pb^{2+}$,$ Ca^{2+}$ , $Bi^{3+}$ , $La^{3+}$ , $Ti^{4+}$ , $Mo^{6+}$ , and $W^{6+}$ ions were made by a solid state reaction. Dielectric constants were measured with temperature. Ferroelectric transition temperature decreased with $Pb^{2+}$ , $Ba^{2+}$ , $La^{3+}$ doping, but the transition temperature increased with $Ca^{2+}$ , $Bi^{3+}$ , $Ti^{4+}$, $Mo^{6+}$ , or$ W^{6+}$ ionic doping. These results show that the ion size plays an important role in the ferroelectricity of SBN ceramic.

Highly Efficient Photocatalysts Based on Lamellar-Shaped Bi2S3 Grown on TiO2 Monolith

  • Li, Kaidi;Zhang, Fangfang;Wang, Huiming;Zhou, Yalan;Zhao, Lixin;Du, Jimin;Gao, Yating;Wang, Weimin;Kang, Dae Joon
    • Nano
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    • v.13 no.9
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    • pp.1850110.1-1850110.13
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    • 2018
  • Here, the lamellar-shaped $Bi_2S_3$ grown on a porous $TiO_2$ monolith was obtained by a two-step method including a sol-gel route and hydrothermal treatment. The photocatalytic activity of the as-synthesized $Bi_2S_3/TiO_2$ composites was evaluated for photodegradation of methylene blue (MB) dye in aqueous solution under the visible-light irradiation. Based on our experimental results, 5% (molar ratio of $Bi_2S_3$ to $TiO_2$) $Bi_2S_3/TiO_2$ photocatalysts exhibited a maximum photodegradation rate of MB up to 96.9% under visible-light irradiation for 120 min. Our findings indicated that the lamellar-shaped $Bi_2S_3$ can extend the light absorption up to visible areas, and porous $TiO_2$ can provide enhanced specific surface area and more mass transfer pathway to enhance the photodegradation efficiency. Furthermore, porous $TiO_2$ can accept the electrons from the $Bi_2S_3$ conduction band due to the relatively positive electrode potential to impede the photoproduced electron and hole combination to result in advanced photocatalytic performance.

Enhancement of Thermoelectric Properties in Cold Pressed Nickel Doped Bismuth Sulfide Compounds

  • Fitriani, Fitriani;Said, Suhana Mohd;Rozali, Shaifulazuar;Salleh, Mohd Faiz Mohd;Sabri, Mohd Faizul Mohd;Bui, Duc Long;Nakayama, Tadachika;Raihan, Ovik;Hasnan, Megat Muhammad Ikhsan Megat;Bashir, Mohamed Bashir Ali;Kamal, Farhan
    • Electronic Materials Letters
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    • v.14 no.6
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    • pp.689-699
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    • 2018
  • Nanostructured Ni doped $Bi_2S_3$ ($Bi_{2-x}Ni_xS_3$, $0{\leq}x{\leq}0.07$) is explored as a candidate for telluride free thermoelectric material, through a combination process of mechanical alloying with subsequent consolidation by cold pressing followed with a sintering process. The cold pressing method was found to impact the thermoelectric properties in two ways: (1) introduction of the dopant atom in the interstitial sites of the crystal lattice which results in an increase in carrier concentration, and (2) introduction of a porous structure which reduces the thermal conductivity. The electrical resistivity of $Bi_2S_3$ was decreased by adding Ni atoms, which shows a minimum value of $2.35{\times}10^{-3}{\Omega}m$ at $300^{\circ}C$ for $Bi_{1.99}Ni_{0.01}S_3$ sample. The presence of porous structures gives a significant effect on reduction of thermal conductivity, by a reduction of ~ 59.6% compared to a high density $Bi_2S_3$. The thermal conductivity of $Bi_{2-x}Ni_xS_3$ ranges from 0.31 to 0.52 W/m K in the temperature range of $27^{\circ}C$ (RT) to $300^{\circ}C$ with the lowest ${\kappa}$ values of $Bi_2S_3$ compared to the previous works. A maximum ZT value of 0.13 at $300^{\circ}C$ was achieved for $Bi_{1.99}Ni_{0.01}S_3$ sample, which is about 2.6 times higher than (0.05) of $Bi_2S_3$ sample. This work show an optimization pathway to improve thermoelectric performance of $Bi_2S_3$ through Ni doping and introduction of porosity.

Effect of post-annealing on the microstructure evolution of sputtered Bi-Te films (후열처리에 따른 Bi-Te 열전박막의 미세구조 연구)

  • Jeon, S.;Lee, H.;Hyun, S.;Oh, M.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.741-742
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    • 2011
  • XRD 결과와 TEM 분석으로부터 열처리효과에 따른 Bi-Te 박막의 미세구조 변화를 확인하였다. $Bi_2Te_3$ 상이 $SiO_2$ 와 Bi-Te 박막의 경계면을 따라서 성장하였고 이는 열전성능에 중요한 영향을 미치는 것을 확인하였다.

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The Reaction of Internal Electrodes with Bi$_2$O$_3$ in Multilayer ZnO Varistor (적층형 ZnO바리스터의 내부전극과 Bi$_2$O$_3$ 와의 반응)

  • Kim, Young-Jung;Kim, Hwan;Hong, Kook-Sun;Lee, Jong-Kook
    • Journal of the Korean Ceramic Society
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    • v.35 no.11
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    • pp.1121-1129
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    • 1998
  • Reactions between Ag-Pd internal electrode materials and{{{{ { {Bi }_{2 }O }_{3 } }} in multilayer chip varistor were in-vestigated. For more than 1 mol%{{{{ { {Bi }_{2 }O }_{3 } }} in varistor composition internal electrode structure was destroyed due to the reaction between internal electrode and{{{{ { {Bi }_{2 }O }_{3 } }} But for typical varistor compositions (below 1 mol% of{{{{ { {Bi }_{2 }O }_{3 } }} content) microstructural changes around the internal electrode were not observed. However SEM-EDS and TEM-EDS analysis showed the uneven distribution of{{{{ { {Bi }_{2 }O }_{3 } }} in the internal electrode which was due to the migration of{{{{ { {Bi }_{2 }O }_{3 } }} to the electorde during sintering. As a results the nonlinear coefficient of multilayer varistor showed very large distribution as well as the breakdown voltage.

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