• Resources Recycling
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• v.27 no.2
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• pp.48-54
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• 2018

Batch ion exchange experiments of Au(III) were performed from ammonium chloride solution by employing strong anionic exchange resins (Amberlite IRA 402 and AG 1-X8). Au(III) was well loaded into the two resins and the loading behavior of Au(III) into AG 1-X8 was superior to that into Amberlite IRA 402. The loading of Au(III) into AG 1-X8 followed Langmuir adsorption isotherm and the experimentally determined loading capacity was 355 mg/g. Au(III) was successfully eluted by $HClO_4$ from the loaded AG 1-X8 and the elution percentage of Au(III) increased with the concentration of $HClO_4$.

• Current Photovoltaic Research
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• v.3 no.1
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• pp.16-20
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• 2015

Ag addition in chalcopyrite materials is known to lead beneficial changes in aspects of structural and electronic properties. In this work, the effects of Ag alloying of $Cu(In,Ga)Se_2$-based solar cells has been investigated. Wide bandgap $(Ag,Cu)(In_{1-x},Ga_x)Se_2$ (x = 0.75~0.8) films have been deposited using a three-stage co-evaporation with various Ag/(Ag+Cu) ratios. With Ag alloying the $(Ag,Cu)(In_{1-x},Ga_x)Se_2$ (x~0.8) films were found to have greater grainsize and film thickness. Device were also fabricated with the $(Ag,Cu)(In_{1-x},Ga_x)Se_2$ (x~0.8) films and their J-V and quantum efficiency measurements were carried out. The highest-efficiency $(Ag,Cu)(In_{1-x},Ga_x)Se_2$ solar cell with Eg > 1.5 eV had an efficiency of 12.2% with device parameters $V_{OC}=0.810V$, $J_{SC}=21.7mA/cm^2$, and FF = 69.0%.

• Journal of the Korean Chemical Society
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• v.33 no.1
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• pp.18-24
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• 1989

Two crystal structures of dehydrated $Ag^+$ and $Rb^+$ exchanged zeolite A, stoichiometries of $Ag_{9}Rb_{3}-A$ (a = 12.278(2)${\AA}$) and $Ag_{10}Rb_{2}-A$ (a = 12.286(2)${\AA}$) per unit cell, have been determined by single crystal x-ray diffraction techniques. Their structures were solved and refined in the cubic space group Pm3m at 21(1)$^{\circ}$C. The crystals of $Ag_{10}Rb_{2}-A$ and $Ag_{10}Rb_{2}-A$ were prepared by flow methods using exchanged solution in which mole ratios of AgNO$_3$ and RbNO$_3$ were 1:5 and 1:50, respectively, with the total concentration of 0.05 M. The structures of the dehydrated $Ag_{9}Rb_{3}-A$ and the $Ag_{10}Rb_{2}-A$ were refined to the final error indices, $R_1$ = 0.064 and $R_2$ = 0.060 with 291 reflections, and $R_1$ = 0.063 and $R_2$ = 0.080 with 416 reflections respectively, for which I >3${\sigma}$(I). In both structures, one reduced silver atom per unit cell was found inside the sodalite cavity. It may be present as a hexasilver cluster in 1/6 of the sodalite units or as an isolated Ag atom coordinated to 4 $Ag^+$ ions in each sodalite unit to give $(Ag_5)^{4+}$, symmetry 4 mm. In the structure of dehydrated $Ag_{9}Rb_{3}-A$, 8 $Ag^+$ ions lie on the threefold axis and each is nearly at the center of the 8-rings at the sites of $D_{4h}$ symmetry. In the structure of dehydrated $Ag_{10}Rb_{2}-A$, two crystallographically different eight 6-ring $Ag^+$ ions were found; $7Ag^+$ ions in the (111) planes of their O(3) framework oxygens and one $Ag^+$ ion inside of sodalite cavity. Two crystallographically different 8-ring cations were also found; two $Rb^+$ ions at the centers of the 8-oxygen rings and one $Ag^+$ ion into the large cavity. Both structures indicate that $Rb^+$ ions prefer to occupy the 8-ring sites, while $Ag^+$ ions prefer to occupy the 6-ring sites.

• Solar Energy
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• v.10 no.3
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• pp.53-59
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• 1990

[ $CdSe_xTe_{1-x}$ ] ($0{\le}x{\le}1$) thin films were deposited cathodically on Ti substrates in aqueous sulfric acid solution containing 1M $CdSO_4$ and 1mM$(TeO_2+SeO_2)$. The limiting current was observed in deposition potential ranging from -0.20 to -0.65 vs.Ag/AgCl ; although its value has changed a little depending on the mole ratio x, the limiting current was almost constant in deposition potential of -0.45V in spite of the change of mole ratio x. The crystal structure of the $CdSe_xTe_{1-x}$ thin films was cubic zinc-blonde in the range of mole ratio $x=0{\sim}0.8$, and hexagonal wurtzite in the mole ratio x=1 When the mole ratio changed from x=0 to x=0.8, diffraction peaks was shifted to the larger diffraction angle.

• Journal of the Korean Chemical Society
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• v.38 no.3
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• pp.186-196
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• 1994

Three fully dehydrated partially $Ag^+$-exchanged zeolite A(Ag_4Na_8-A, Ag_6Na_6-A, and Ag_8Na_4-A) were treated at $250^{\circ}C$ with 0.1 torr Rb vapor at 4 h. Their structures were determined by singlecrystal X-ray diffraction methods in the cubic space group $Pm{\bar3}m$ (a = 12.264(4) $\AA$, a = 12.269(1) $\AA$, and a= 12.332(3) $\AA$, respectively) at $22(1)^{\circ}C$, and were refined to the final error indices, R(weighed), of 0.056 with 131 reflections, 0.068 with 108 reflections, and 0.070 with 94 reflections, respectively, for which I > $3\sigma(I).$ In these structures, Rb species are found at three different crystallographic sites; three $Rb^+$ ions per unit cell are located at 8-ring centers, ca. 6.0∼6.8 $Rb^+$ ions are found opposite 6-rings on threefold axes in the large cavity, and ca. 2.5 $Rb^+$ ions are found on three fold axes in the sodalite unit. Also, Ag species are found at two different crystallographic sites; ca. 0.6∼1.0 $Ag^+$ ion lies opposite 4-rings and about 1.8∼4.2 Ag atoms are located near the center of the large cavity. In these structures, the numbers of Ag atoms per unit cell are 1.8, 3.0, and 4.2, respectively, and these are likely to form hexasilver clusters at the centers of the large cavities. The $Rb^+$ ions, by blocking 8-rings, may have prevented silver atoms from migrating out of the structure. Each hexasilver cluster is stabilized by coordination to 6-ring, 8-ring $Rb^+$ ions, and also by coordination to a 4-ring $Ag^+$ ion.

• Clean Technology
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• v.21 no.4
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• pp.271-277
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• 2015

A photocatalyst which mixed by the commercialized P25-TiO₂ and a synthesized Ag_xO was used in an appropriate weight ratio to effectively produce hydrogen gas in this study. The Ag_xOs were synthesized with the conventional sol-gel method, and tetramethylammonium hydroxides were added at the synthesis process in order to stabilize the solutions, and then the solutions were heat-treated at the temperatures of -5, 25, and 50 ℃, resulted to obtain the three types of silver oxides. Physicochemical properties of the synthesized Ag_xOs were identified through X-ray diffraction analysis (XRD), scanning emission microscopy (SEM), ultraviolet-visible spectroscopy, and X-ray photoelectron spectroscopy (XPS). In the photolysis results of water/methanol (weight ratio 1:1) solution, the mixture of P25-TiO₂/Ag_xO exhibited a significantly higher hydrogen gases evolution, compared to that of pure P25-TiO₂. Additionally, the addition of H₂O₂ as an supplement oxidant and in Ag_xO synthesized at 50 ℃ improved the hydrogen production efficiency. In particular, the emitted hydrogen gases reached to 13,000 μmol during 8 hours when a mixed catalyst, Ag_xO of 0.1 g and P25-TiO₂ of 0.9 g, were used.

• Journal of the Korean Chemical Society
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• v.32 no.6
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• pp.520-527
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• 1988

The crystal structures of $Co^{2+}\;and\;Ag^+\;exchanged\;zeolite\; A,\; Ag_6Co_3$-A(a = 12.131(5)$\AA$) and $Ag_3Co_{4.5}$-A(a = 12.145(1)$\AA$), have been determined by single crystal X-ray diffraction techniques. Both structures were solved and refined in the cubic space group Pm3m at 21(1)$^{\circ}C$. Full-matrix leastsquares refinement converged to the final error indices of R1 = 0.045 and R2 = 0.041 for $Ag_3Co_{4.5}-A,\; and\; R1 = 0.066\; and\; R2 = 0.076\; for\; Ag_6Co_3$-A using the 258 and 189 reflections, respectively, for which I > 3$\sigma$(I). Both structures indicate that CO(Ⅱ)ions are coordinated by three framework oxygens; the Co(II) to O(3) distances are 2.118(4)$\AA$ for $Ag_3Co_{4.5}$-A and 2.106(1)$\AA$ for $Ag_6Co_3-A$, respectively. In each structure, the angle substended at Co(II), O(3)-Co(II)-O(3) is ca 120°, close to the idealized trigonalplanar value. $Co^{2+}$ ions prefer to 6-ring sites and $Ag^+$ ions prefer to 8-ring site when total number of cations is more than 8. The crystals of hydrated and dehydrated $Ag_{12-2x}Co_x-A (x > 4.5)$ had no crystalline diffraction pattern, indicating the apparent exchange limit of $Co^{2+}\; into\; Ag_{12}-A\; is\; 4.5 Co^{2+}$ ions per unit cell. $Co^{2+}$ ions hydrolyze $H_2O$ molecules and $H_3O^+$ concentraction is accumulating. These $H_3O^+$ ions destroy the zeolite structures.

• Journal of the Korean Chemical Society
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• v.38 no.9
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• pp.621-627
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• 1994

Two crystal structures of dehydrated, $Ag^{+}$ and $Ca^{2+}$-exchanged zeolite A treated at $250^{\circ}C$ with 0.15 torr of Cs vapor have been determined by single-crystal X-ray diffraction technique in the cubic space group $Pm{\bar\3m$ at $21(1)^{\circ}C$ (a = 12.344(2) $\AA$ and 12.304(2) $\AA$). Their structures were refined to the final error indices, R (weighted), of 0.091 with 180 reflections, and 0.093 with 179 reflections, respectively, for which I > $3\sigma(I).$ In each structure, Cs species are found at four different crystallographic sites: 3 $Cs^{+}$ ions per unit cell are located at 8-ring centers, ca. 6.81∼7.14 $Cs^{+}$ ions are found on opposite 6-rings on threefold axes in the large cavity, ca. 1.93∼2.03 $Cs^{+}$ ions are found on threefold axes in the sodalite unit, and 0.53∼0.66 $Cs^{+}$ ions lie on opposite 4-rings. Also, ca. 4.12∼4.27 Ag atoms are located near the center of the large cavity. In these structures, excess cesium atoms in a unit cell are associated with other $Cs^{+}$ ions on a single threefold axis to form the linear cationic cluster $(Cs_4)^{3+}$. By blocking 8-rings, the $Cs^{+}$ ions may have prevented silver atoms from migrating out of the structure. The Ag atoms are likely to have formed hexasilver clusters at the centers of the large cavities. Each hexasilver cluster is stabilized by coordination to 14 $Cs^{+}$ ions.

• Bulletin of the Korean Chemical Society
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• v.23 no.12
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• pp.1759-1764
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• 2002

Two crystal structures of dehydrated $Ag^+-andTl^+$-exchanged zeolite X$Ag_{27}Tl_{65-}X\;and\;Ag_{23}Tl_{69-}X$have been determined by single-crystal X-ray diffraction techniques in the cubic space group Fd3 at 21(1) $^{\circ}C(a=24.758(4)\AAa=24.947(4)$, ${\AA}respectively).$, Their structures were refined to the final error indices $R_1$=0.055 and $wR_2$=0.057 with 375 reflections, and $R_1$=0.057 and $wR_2$=0.057 with 235 reflections, respectively, for which I > $3\sigma(I).$ In the structure of $Ag_{27}Tl_{65-}X,\;27\;Ag^+$ ions were found at two crystallographic sites: 15$Ag^+$ ions at site I at the center of the hexagonal prism and the remaining 12$Ag^+$ ions at site II' in the sodalite cavity. Sixty-five $Tl^+$ ions were located at three crystallographic sites: 20$Tl^+$ ions at site II opposite single six-rings in the supercage, 18$Tl^+$ ions at site I' in the sodalite cavity opposite the D6Rs, and the remaining 27$Tl^+$ ions at site III' in the supercage. In the structure of $Ag_{23}Tl_{69-}X$, 23$Ag^+$ ions were found at two crystallographic sites: 15 at site I and 8 at site II'. Sixty-nine $Tl^+$ ions are found at four crystallographic sites: 24 at site II, 17 at stie I', and the remaining 28 at two III' sites with occupancies of 22 and 6.

• Journal of the Korean Chemical Society
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• v.33 no.5
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• pp.452-458
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• 1989

The crystal structures of vacuum-dehydrated $Ag^+\;and\;Ca^{2+}$ exchanged zeolite A, Ag_7Ca_{2.5}-A(a = 12.310(1){\AA})$ and $Ag_2Ca_5-A(a = 12.287(2){\AA})$ have been determined by single-crystal X-ray diffraction methods in the cubic space group Pm3m at $21(1)^{\circ}C$. The crystals of $A_7Ca_{2.5}-A\;and\;Ag_2Ca_5-A$ were prepared by flow method using exchange solutions in which mole ratios of $AgNO_3\;and\;Ca(NO_3)_2$ were 1:50 and 1:1000, respectively, with total concentration of 0.05 M. Full-matrix least-squares refinement converged to the final error indices of R1 = 0.056 and R2 = 0.059 for $Ag7Ca2.5-A$, and R1 = 0.054 and R2 = 0.082 for $Ag2Ca5-A$ using 306 and 348 reflections, respectively, for which I >3 {\sigma}$ (I). 5.5 $Ag^+$ ions and 2.5 Ca^{2+}$ ions for $Ag_7Ca_{2.5}-A\;and\;2\;Ag^+$ ions and 5 $Ca^{2+}$ ions for $Ag_2Ca_5-A$ lie on two crystallographically nonequivalent threefold axes on the 6-rings. Both structures indicate that smaller Ca2+ ions preferentially occupy 6-ring sites and larger $Ag+$ ions occupy 8-ring sites when total number of cations per unit cell is more than 8.