Sodium Alginate-Assisted Synthesis of PdAg Bimetallic Nanoparticles and their Enhanced Activity for Electrooxidation of Ethanol

Yanru Yin,Changna Wen,Ning Ma,Baoyan Wang,Lianying Zhang,Hongliang Li,Peizhi Guo 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.9

Palladium and palladium-silver bimetallic nanocrystals have been synthesized hydrothermally by using environmental-friendly sodium alginate as the stabilizer and reducing agent. The pure palladium nanoparticles were spherical-like possibly due to the principle of the lowest surface energy, however, the formation of bimetallic palladium-silver nanoparticles was much more complicated, which was thinner and more irregular nanostructures than pure palladium nanoparticles. Electrochemical measurements showed that the electrocatalytic activity toward ethanol oxidation was increased first with the increase of silver content in bimetallic nanoparticles, from pure palladium of around 1070 mA/mg, to PdAg-20 of 1160 mA/mg and to PdAg-10 of 1750 mA/mg, and declined greatly at a high content of silver, approximately 279 mA/mg. Electrochemical stability test showed that PdAg-10 and PdAg-5 were the best and worst among four palladium-based samples, respectively. Based on the experimental data, the formation mechanism of pure palladium and palladium-silver bimetallic nanoparticles and the structure-property relationship of these samples have been discussed.

Highly Selective and Simple Zero and First Order Derivative Spectrophotometric Determination of Palladium by Using α-Benzilmonoxime in Triton X-100 Micellar Solution

Eskandari, Habibollah,Karkaragh, Gholamhassan Imanzadeh Korean Chemical Society 2003 Bulletin of the Korean Chemical Society Vol.24 No.12

The reaction of ${\alpha}$-Benzilmonoxime with palladium(II) produces a green complex in triton X-100 micellar media. Palladium has been determined using zero and first derivative spectrophotometric methods. The absorbances of Pd(II)- ${\alpha}$--benzilmonoxime complex at 441.8 and 677.0 nm in 0.10 M perchloric acid solution were monitored and linear working ranges of 0.3-12.0 and 0.7-20 ${\mu}$g mL$^{-1}$ with detection limits of 0.07 and 0.10 ${\mu}$g $mL^-1$ were obtained, respectively. Also, recoveries in the range of 92.8 to 100.1% and relative standard deviations in the range of 0.4 to 7.1% were obtained. First derivative spectrophotometry has also been applied for palladium determination under the optimum condition. The linear dynamic range of 0.2-24.0 ${\mu}$g $mL^{-1}$ palladium with relative standard deviations of 0.6-6.9% and recoveries in the range of 94.9-102.5% has been obtained by first derivative spectrophotometry. The method shows high selectivity because of the high concentration of acid used, which prevents formation of complexes of ${\alpha}$--benzilmonoxime with the other cations. The palladium complex formed was stable at least one day. The method was successfully applied to the determination of palladium in some synthetic palladium alloys and palladium-charcoal powder.

Preparation of Nanosized Palladium-Graphene Composites and Photocatalytic Degradation of Various Organic Dyes

( Jae Jin Kim ),( Weon Bae Ko ) 한국고무학회 2016 엘라스토머 및 콤포지트 Vol.51 No.1

Nanosized palladium particles were synthesized using palladium(II) chloride, trisodium citrate dihydrate, and sodium borohydride under stirring condition. Nanosized palladium-graphene composites were prepared from palladium nanoparticles, and graphene was enclosed with polyallylamine under stirring condition for 1 h followed by ultrasonication for 3 h. Nanosized palladium-graphene composites were heated in an electric furnace at 700 °C for 2 h and characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. UV-vis spectrophotometry was used to evaluate the nanosized palladium-graphene composites as a catalyst in the photocatalytic degradation of various organic dyes such as methylene blue, methyl orange, rhodamine B, and brilliant green under ultraviolet light at 254 nm.

Palladium-Zeolite nanofiber as an effective recyclable catalyst membrane for water treatment

Choi, Jungsu,Chan, Sophia,Yip, Garriott,Joo, Hyunjong,Yang, Heejae,Ko, Frank K. Elsevier 2016 Water research Vol.101 No.-

<P><B>Abstract</B></P> <P>Zeolite is an exciting natural material due to its unique capability of ammonium nitrogen (NH<SUB>3</SUB> N) adsorption in water. In this study, multifunctional hybrid composites of zeolite/palladium (Ze/Pd) on polymer nanofiber membranes were fabricated and explored for sustainable contaminant removal. SEM and XRD demonstrated that zeolite and palladium nanoparticles were uniformly distributed and deposited on the nanofibers. NH<SUB>3</SUB> N recovery rate was increased from 23 to 92% when palladium coated zeolite was embedded on the nanofiber. Multifunctional nanofibers of Ze/Pd membranes were able to adsorb NH<SUB>3</SUB> N on the zeolites placed on the surface of fibers and palladium catalysts were capable of selective oxidation of NH<SUB>3</SUB> N to N<SUB>2</SUB> gas. The cycling of NH<SUB>3</SUB> N adsorption-oxidation, high flux, hydrophilicity, and flexibility of the membrane makes it a strong candidate for water treatment.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Zeolite and palladium nanoparticles were uniformly deposited on the nanofibers. </LI> <LI> Palladium catalysts were capable of selective oxidation of NH<SUB>3</SUB> N to N<SUB>2</SUB> gas. </LI> <LI> Multifunctional nanofibrous membranes were able to absorb and remove NH<SUB>3</SUB> N. </LI> <LI> Ze/Pd nanofiber membrane can be recycled and reused for NH<SUB>3</SUB> N removal. </LI> <LI> Recovery rate of Ze/Pd membranes functions were shown to be 92.2% at 250 °C. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Highly selective FET-type glucose sensor based on shape-controlled palladium nanoflower-decorated graphene

Shin, Dong Hoon,Kim, Wooyoung,Jun, Jaemoon,Lee, Jun Seop,Kim, Jae Hyun,Jang, Jyongsik Elsevier 2018 Sensors and actuators. B Chemical Vol.264 No.-

<P><B>Abstract</B></P> <P>The glucose concentration in human body fluids is main marker for diagnose diabetes mellitus, which is a disease caused by insufficient insulin. Although diagnostic devices based on glucose level in the blood have been commercialized, a non-invasive detection methodology is required. Here, selectivity enhanced field-effect-transistor (FET)-type glucose sensor based on shape-controlled palladium nanoflower-decorated CVD graphene (SPNFG) with glucose oxidase (GOx) and nafion was fabricated using surface functionalization, electrodeposition and spin coating techniques. The surface-functionalized CVD graphene is used as substrate for electrodeposition and a p-type channel for FET-type sensor. The palladium nanoflower (PNF) shape was controlled by adjusting the sulfuric acid concentration in the electrolyte during the electrodeposition. Nafion and GOx layer were deposited onto SPNFG using spincoating method. The GOx/Nafion/SPNFG electrode within FET system was applied to high sensitive and selective glucose sensor. The GOx/Nafion/SPNFG based sensors exhibit high selectiviy for uric acid and ascorbic acid with low minimum detection limit for glucose (1 nM). and The high durability can be expected for the FET-type sensor by virtue of direct decoration of palladium on the CVD graphene surface.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Palladium nanoflower decorated CVD graphene (PNFG) is successfully fabricated by using surface functionalization and electrodeposition. </LI> <LI> Shape of PNF was easily regulated by adjusting the concentration of sulfuric acid (H<SUB>2</SUB>SO<SUB>4</SUB>) in the electrolyte. </LI> <LI> Adopting the nafion as blocking layer for non-target material, nafion prohibits the access of non-target molecules to PNF. </LI> <LI> On the other hand, glucose (target-molecule) dissociated into hydrogen peroxide (H<SUB>2</SUB>O<SUB>2</SUB>) by GOx and reaction between Pd and H<SUB>2</SUB>O<SUB>2</SUB> make current change. </LI> <LI> Owing to FET-type, minimum detectable level is 1 nM. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P> <B>The high selective FET-type glucose sensor based on GOx/Nafion/SPNFG is fabricated.</B> The high selective FET-type glucose sensor based on GOx/Nafion/SPNFG is fabricated. The detection limit is a 1 nM and sensitivity is increases with sharpening the shape of palladium. Also high selectivity is achieved by nafion layer and glucose.</P> <P>[DISPLAY OMISSION]</P>

팔라디움 복합막의 제조 및 응용

남승은,이규호 한국공업화학회 2002 공업화학 Vol.13 No.3

팔라디움(Pd)계 막들은 수소에 대한 선택투과도가 매우 높아서 고온의 혼합 기체 중에서 고순도 수소기체의 분리에 효과적으로 이용되고 있으며 탈수소 반응 등과 연계되어 많은 연구가 이루어져왔다. 순수한 팔라디움 금속 막의 경우 수소를 투과하면 수소농도에 따라 α 상 이외에 β 상이 형성되어 격자 평창에 의한 뒤틀림 현상이 발생하여 부스러지기 쉬우며 이를 보완하기 위해 니켈, 구리, 은 등 다른 금속과의 합금이 반드시 요구된다. 또한 높은 수소투과 속도와 기계적 강도를 함께 유지하기 위해 복합막 형태의 팔라디움 막이 제조되며 복합막 제조시 박막의 핀홀을 최소화하고 장기적 안정성을 유지하는 것이 매우 중요한 문제이다. 이러한 팔라디움 막을 막반응기에 활용함으로써 탈수소 반응이나 수증기 개질 반응 등의 반응효율을 크게 높일 수 있다. 본고에서는 팔라디움 막의 구조 및 수소와 다른 기체투과 메카니즘, 여러 팔라디움 복합막 제조 방법 및 이에 따른 특성 그리고 이들의 응용분야에 대해 살펴보고자 한다. Palladium(Pd) and palladium alloy membranes, which are well-known nonporous membranes with high perm-slectivity of hydrogen, have been used to separate hydrogen of high purity from vatious gas mixtures. The study of these membrane systems as hydrogen separation membranes and membrane reactors has been rather extensive for the past several decades. Pd alloys with other metals such as nickel, copper and silver are preferred over pure Pd, since pure Pd is subject to the α-β phase transformation due to the adsorption of hydrogen, which changes the atom spacing in the metal lattice and becomes brittle after repeated cycles of hydrogen sorption and desorption. For high flux of hydrogen permeation together with mechanical stability, Pd membranes have been mostly composite type structure with thin coating layer over a memchanically strong porous supporting layer. Minimization of pin holes and maintenance of long term stability of thin coating layer are very important factors in the preparation of composit membranes. The reaction effeciency of de-hydrogenation and water vapor reforming reaction was improve by the membrane reactors made with these palladium membranes. In this paper the structure of palladium membranes, the transport mechanism of hydrogen and gases, the preparation and characteristics of various composite palladium membranes and their applications will be discussed.

18K White Gold의 백색 색상 개선에 관한 연구

정갑주 ( Kap-joo Jung ),안일훈 ( Ahn Il-hoon ) 한국디자인트렌드학회 2021 한국디자인포럼 Vol.26 No.1

연구배경 1900년대 초반 다이아몬드 광산이 다량 발견되면서 다이아몬드와 잘 어울리는 백색 주얼리의 호황기가 시작되었다. 이로 인해 백금(Pt)을 소재로 한 주얼리는 시간이 갈수록 소비자들의 선호성이 높아졌지만, 백금의 채굴 생산은 감소하여 공급에 차질이 발생하게 된다. 이러한 백금의 대체제로 백금과 비슷한 느낌을 주는 백색 합금 금(白色 合金 金)이 상업적 목적에 의해 개발 유통된 것이 White Gold(이하 WG)의 시초다. 초기의 WG는 합금으로 사용되는 원소 금속의 종류나 함량 등이 일률적이지 않았지만, 차츰 정형화 된 WG 제작 방법이 생겨나게 되는데 그 제작 방법에 따라 니켈(Ni)계 WG와 팔라듐(Pd)계 WG 두 가지로 나눌 수 있다. 하지만 현대에서 제작되는 WG에는 니켈이나 팔라듐이 주로 사용되지 않는데, 니켈은 접촉 알러지 성분을 유발하여 신체에 해로운 영향을 끼치며 팔라듐은 가격이 폭등하여 금과 비슷한 경제적 가치를 가지고 있어 경쟁이 극심한 현대 시장에서 경제적인 가격을 제시 할 수 없기 때문이다. 그럼에도 불구하고 일부 명품 브랜드 주얼리 기업에서는 WG 주얼리에 팔라듐이나 백금을 알로이 합금 재료로 사용하여 제작하기도 한다. 이러한 방식으로 제작 된 WG는 맑은 백색을 가지게 되는데 변색의 우려가 없으며 백색 색상 도금을 하지 않아도 꾸준히 백색 색감이 유지되므로 과거의 방식을 고수한 명품 브랜드들이 재료비 상승에도 불구하고 스스로의 가치를 지켜온 것이라 볼 수 있다. 연구방법 과거의 국내 팔라듐계 WG 합금 비율은 4:4:2 비율로 금 40%, 팔라듐 40%, 은과 백금 등 기타 금속의 합 20%로 제작 되었는데 주조기법이 활성화되기 이전으로 핸드메이드 방식으로 제작하고 백색 도금으로 마무리하여 판매해왔다. 이러한 방법을 기반으로 도금이 필요 없는 WG를 개발하되, 경제적 가치를 고려한 합금 알로이를 제작하고자 하였다. 40%의 금으로 제작 된 합금은 9~10K정도 되지만 본 연구에서는 가장 보편적이고 주얼리 소재로 적합한 18K 함량 한 가지에 대한 백색 색상에 대해 연구하고자 하였다. 18K는 75%의 금이 주소재이므로 나머지 25%의 알로이가 백색 색상 개선에 관한 실험 연구이다. 백색 색상을 간섭하는 금속 원소들을 최대 15%까지 알로이로 합금하여 백색 색상 개선이 이루어졌는지를 비교 분석 하였으며 그중 색상 개선이 이루어진 개체는 연마 과정을 통해서 실제 주얼리 제작시 가공에 이상이 없는지, 시간이 지날수록 변색이 일어나는지, 광내기 작업 후에도 백색 광택이 꾸준히 유지되는지 연구 하였다. 또한 고가의 알로이 재료가 사용 될 경우 경제성을 고려하여 알로이 함량을 차츰 줄여가며 제작하고, 만들어진 개체들을 비교분석 하여 최소한의 가치로 최대의 효과를 거둘 수 있는 황금비율을 제시하였다. 연구결과 고가의 알로이로 인한 합금 자체의 고비용과 그로 인한 제품 가격 증대라는 단점도 존재하지만 색상개선을 통해 주얼리 제품 자체의 품질이 향상되고 불필요한 도금 지출 비용을 줄이면 소매점에서 귀금속 상품 진열에 대한 안정성을 높일 수 있게 되며, 저가의 기존 WG와 고가의 WG라는 새로운 색상의 라인업을 구성 할 수 있게 될 것이다. 무엇보다 WG의 변색으로 인한 판매상의 부득이한 해명이 필요치 않아 판매성과를 높일 수 있으며 변색이 발생하지 않으므로 소비자들의 불만이 해소되어 더욱 다양한 WG 주얼리 구매에 거부감이 없어지게 될 것이다. 결론 연구의 결과로 나타난 이로운 효과는 주얼리 시장 경제에 많은 도움이 될 것으로 기대가 되며, 주얼리 제조업계를 비롯한 도ㆍ소매 유통업계 등 모든 주얼리 분야에 경제적 선순환 역할을 하게 될 것으로 기대한다. Background White color jewelrys can be said to have been booming since a large number of diamond mines were discovered in the early 1900s. However, while demand for platinum increases over time, the production of platinum decreases, causing disruptions in supply. White gold, which is similar to platinum, is developed and distributed for commercial purposes when such a platinum substitute is desperately needed. Early white gold was not uniform in the type and content of elemental metals used as alloys, Gradually, the production method of standardized white gold will be created. According to the production method, it can be divided into nickel-based white gold and palladium-based white gold. However, nickel and palladium are not commonly used in modern white gold. Nickel causes contact allergens to cause harmful effects on the body, and palladium has soaring prices that have similar economic value to gold and cannot offer economic prices in a highly competitive modern market. Nevertheless, some luxury brand jewelery companies use palladium or platinum as alloy alloys in white gold jewelry. White gold produced in this way will have a clear white color without worry of discoloration. The white color is steadily maintained even without white plating, which means that luxury brands have kept their values. Methods In the past, the palladium-based white gold alloy ratio was 4: 4: 2, which was made of 40% of gold, 40% of palladium, and 20% of other metals such as silver and platinum. Based on this method, white gold without plating was developed. And alloy alloy considering economic value was intended. Alloys made of 40% gold range from 9 to 10K, but this study attempted to study the white color of one of the most popular and jeweled 18K content. Since 18K is 75% gold, the remaining 25% alloy is the main experimental study on white color improvement. Several metal elements that induce white color are selected and alloyed with alloys up to 25%, the maximum ratio, to compare white color improvement. Among them, the subjects whose color improvements were made were studied whether or not there was any abnormality in the processing of the actual jewelry, the discoloration occurred over time, and whether the white luster was maintained even after the polishing operation. In addition, when expensive alloy material is used, it is produced by gradually reducing the alloy content in consideration of economical efficiency. By comparing and analyzing the created objects, the golden ratio that can achieve the maximum effect with the minimum value is presented. Result Such research has disadvantages such as the high cost of alloys due to expensive alloys and the resulting increase in product prices, but color improvement can improve the quality of jewelry products and reduce unnecessary plating expenses. The retailer will be able to increase the stability of the display of precious metal products and will be able to construct a new color lineup of low priced existing white gold and expensive white gold. First of all, the seller's excuses due to the discoloration of white gold are unnecessary. It can improve sales performance and resolve dissatisfaction with consumers due to no discoloration. Consumers will also buy more jewelry. Conclusion The beneficial effects of these studies are expected to be of great benefit to the jewelry market economy. It is expected to play an economic virtuous circle in all jewelry sectors, including the jewelry manufacturing industry and the wholesale and retail distribution industry.

Di-n-Hexyl Sulfide 함유 지지액막을 통한 팔라듐의 투과 특성

안재우,정진기,이재천 대한금속재료학회 2003 대한금속·재료학회지 Vol.41 No.9

The transport of palladium through supported liquid membranes from hydrochloric acid solution has been investigated. Di-n-Hexyl Sulfide(DHS) has been stuided as a mobile carrier for the facilitated transport of Pd(Ⅱ) and kerosene as a diluent. Ammonium hydroxide solution has been employed as a stripping agents. The transport behavior of Pd(Ⅱ) was studied at various factors such as concentration of hydrochloric acid in feed solution, ammonium hydroxide in stripping solution, DHS in membrane phase, palladium in feed solution and the effect of stirring speed. The separation of palladium from palladium-platinum mixed solutions has also been investigated.

Atomistic simulations of PdTi high-temperature shape-memory alloys

Ko, Won-Seok,Jeon, Jong Bae Elsevier 2018 INTERMETALLICS Vol.102 No.-

<P><B>Abstract</B></P> <P>Martensitic phase transformations in palladium-titanium high-temperature shape-memory alloys (HTSMA) are studied using molecular dynamics simulations. On the basis of the second nearest-neighbor modified embedded-atom method formalism, an interatomic potential for the binary palladium-titanium system is determined by improving the unary descriptions of pure palladium. The developed interatomic potential accurately reproduces physical properties at the equiatomic composition and the resultant temperature- and stress-induced phase transformations between B2 austenite and B19 martensite structures. Subsequent large-scale molecular dynamics simulations demonstrate that the developed potential can be successfully utilized to investigate atomic details of phase transformations in nanocrystalline palladium-titanium alloys.</P> <P><B>Highlights</B></P> <P> <UL> <LI> An interatomic potential for the palladium-titanium high-temperature shape-memory alloys is now available. </LI> <LI> Temperature- and stress-induced martensitic phase transformations are studied using molecular dynamics simulations. </LI> <LI> Nanocrystalline cells indicate the full recovery of the initial structure after thermal and mechanical cyclic loadings. </LI> </UL> </P>

초음파를 이용한 수소 연료 자동차용 알루미늄 박판 기반 수소 검출 센서

송형두(Hyeong-Doo Song),김시습(Si-Seup Kim),전인수(In-Su Jeon),양성모(Sung-Mo Yang),기창두(Chang-Doo Kee) 한국자동차공학회 2011 한국자동차공학회 부문종합 학술대회 Vol.2011 No.5

We have developed an aluminum thin plate based hydrogen sensor to detect hydrogen leakage of a hydrogen fuel cell vehicle using ultrasonic wave. This sensor consists of a piezoelectric sensor which generates and receive ultrasonic wave, and an aluminum plate coated with palladium and platinum. Ultrasonic wave is guided and propagated through aluminum plate coated with palladium and platinum. In situation of hydrogen leakage, the density of the palladium layer is changed because hydrogen molecules were adsorbed and inflated in palladium. Futhermore, the changed density of the palladium layer causes the change of the propagation behavior of the ultrasonic wave. As a result, the amplitute of output voltage corresponding to that of wave has gradually damped by increased concentration of hydrogen gas. According to this study, it is confirmed the aluminum thin plate based hydrogen sensor is suitable to detect the hydrogen leakage of a hydrogen fuel cell vehicle.