Bi_2O_3-B_2O_3-WO_3系统微晶玻璃的制备

采用熔融法制备了0.97[x Bi2O3(1-x)B2O3]·0.03WO3(0.25≤x≤O.75)基础玻璃,通过差热分析确定玻璃的特征温度,经热处理制备微晶玻璃.结果表明所制备的玻璃中只有x =0.67和x=0.60两个组成经热处理生成了微晶玻璃,颜色为乳黄色,晶相分别为BiO2和Bi2WO6,在扫描电镜下观察两种晶体的形貌均为颗粒状,晶粒尺寸在0.8～1.0μm.该体系玻璃的密度较大而硬度较小,但热处理后的微晶玻璃的密度和硬度均大于处理前的基础玻璃.     

ZnBi38O60/Bi2O3 photocathode for hydrogen production from water splitting

Hydrogen production from water splitting into photoelectrochemical cells is a promising alternative for reducing the use of fossil fuels. Here, we synthesize by spray pyrolysis a porous ZnBi₃₈O₆₀/γ-Bi₂O₃ film with a surface area of 744 m² g⁻¹ for use as a photocathode in water-splitting cells. The film of ZnBi₃₈O₆₀ with 3 wt% Bi₂O₃ has 2.3 eV bandgap energy and a conduction band energy of −2.14 V vs. RHE at pH 6.99, which is thermodynamically suitable for reducing H⁺ to H₂. Under illumination, the film produces a current density of −1.55 mA cm⁻² at 0 V vs. RHE with an onset potential of 0.84 V vs. RHE. HC-STH efficiency is 0.09% at 0.17 V vs. RHE and IPCE at 0 V vs. RHE is 3.8% at 480 nm. Under continuous operation, the ZnBi₃₈O₆₀/γ-Bi₂O₃ film shows a stable photocurrent of −0.4 mA cm⁻² at 0 V vs. RHE for 1800 s with 100% Faradaic efficiency.     

Suppression of phosphor‐glass reactions in YAG:Ce phosphor‐embedded glasses

For high‐power white LED applications, YAG:Ce‐based yellow phosphors were embedded in a low‐T_g Bi₂O₃–B₂O₅–ZnO–Sb₂O₅ glass (BiG) by sintering route. A high‐T_g silicate glass (SiG) was also used for comparison. Dense (porosity<2%) phosphor‐glass composites were obtained after sintered at 800°C (for SiG) and 325°C (for BiG). XRD quantitative analysis indicates that the loss of phosphor content is in the range of 2.5%‐22%, caused by partial dissolution of phosphor particles into the glass matrix during sintering. The element distribution across the interface and within the reaction zone between phosphor and glass was analyzed by TEM/SEM‐EDS. The intrinsic emission characteristic of YAG:Ce is nearly not altered, possibly resulted from the slight modification of the YAG phase during sintering. Thus the final emission intensity of the sintered body is mainly determined by the residual amount of the YAG:Ce phase. Replace the high‐T_g SiG glass by the low‐T_g BiG glass, prenitridize the YAG:Ce phosphor, and change the sintering atmosphere from air to N₂ suppress the loss of phosphor during sintering. Therefore, the resulting loss of emission intensity of the phosphor‐embedded glass material can be reduced to only about 1.8%.     

CuO/CuBi2O4 bilayered heterojunction as an efficient photocathode for photoelectrochemical hydrogen evolution reaction

The poor photostability and low photoactivity are two bottlenecks limiting the application of CuO and CuBi₂O₄ as competitive candidates for photoelectrochemical (PEC) hydrogen evolution reaction (HER). To overcome the bottlenecks, we constructed a novel CuO/CuBi₂O₄ bilayered structure for PEC HER. The underlying CuO layer functions as the main photoabsorber, while the outside CuBi₂O₄ layer acts as a protection shield. After further decorated with the NiO_x electrocatalysts, the CuO/CuBi₂O₄/NiO_x photocathode exhibits a high photoactivity and remarkable photostability. We ascribe this excellent performance to the following factors: (1) the bilayer structure improves light harvesting efficiency, (2) the outside CuBi₂O₄ enhances the photostability, (3) the favorable band alignment increases charge separation efficiency, and (4) the presence of NiO_x facilitates the charges transfer at the interface. Therefore, this work not only sets a new benchmark efficiency for the CuO and CuBi₂O₄ heterojunction, but also provides principles for designing layered heterojunction for PEC water splitting.     

氯氧铋湿法直接制取铋盐新工艺研究

研究了氯氧铋湿法直接制取铋盐新工艺，研究结果表明，该工艺流程合理，铋回收率高，对环境污染小。     

In Situ Formation of Hierarchical Bismuth Nanodots/Graphene Nanoarchitectures for Ultrahigh‐Rate and Durable Potassium‐Ion Storage

Metallic bismuth (Bi) has been widely explored as remarkable anode material in alkali‐ion batteries due to its high gravimetric/volumetric capacity. However, the huge volume expansion up to ≈406% from Bi to full potassiation phase K₃Bi, inducing the slow kinetics and poor cycling stability, hinders its implementation in potassium‐ion batteries (PIBs). Here, facile strategy is developed to synthesize hierarchical bismuth nanodots/graphene (BiND/G) composites with ultrahigh‐rate and durable potassium ion storage derived from an in situ spontaneous reduction of sodium bismuthate/graphene composites. The in situ formed ultrafine BiND (≈3 nm) confined in graphene layers can not only effectively accommodate the volume change during the alloying/dealloying process but can also provide high‐speed channels for ionic transport to the highly active BiND. The BiND/G electrode provides a superior rate capability of 200 mA h g^?1 at 10 A g^?1 and an impressive reversible capacity of 213 mA h g^?1 at 5 A g^?1 after 500 cycles with almost no capacity decay. An operando synchrotron radiation‐based X‐ray diffraction reveals distinctively sharp multiphase transitions, suggesting its underlying operation mechanisms and superiority in potassium ion storage application.     

钛及钛合金封接用无铅玻璃的制备及封接性能初探

为满足工业生产对无铅封接玻璃的需求,研制了一种用于钛及钛合金封接的铋酸盐系玻璃。测试了该铋酸盐玻璃的膨胀系数及润湿角,考察了其与TA1纯钛、TC4钛合金的封接效果。结果表明,所制备的铋酸盐玻璃的线性膨胀系数为8．96×10-6K-1,可与TA1、TC4实现匹配封接。此外,该铋酸盐玻璃具有良好的润湿性,在大气气氛下封接件的强度达1730N,高于惰性气体保护下封接件的强度。最后提出了今后将进一步优化和改进铋酸盐玻璃配方,降低封接温度,优化封接工艺,提高封接件的可靠性。     

表面活性剂增敏I3^—间接光度法测定硅灰石和水中锰

提出了用铋酸钠氧化Mn~(2+)为MnO_4~-,MnO_4~-氧化I~-为I_2进而生成I_3~-,在350nm处测I_3~-吸光度,间接测定锰含量方法。加入TPC有明显增敏和掩蔽作用,灵敏度和选择性较好。实测硅灰石中锰含量,相对标准偏差(RSD)为1.5％;实测天然水中锰含量,RSD为1.9％～4.9％,回收率为94.2％～106.2％     

Diamylamylphosphonate Solvent Extraction of Am(VI) from Nuclear Fuel Raffinate Simulant Solution

The separation of hexavalent americium from the lanthanides in simulated PUREX raffinate solution using 1 M diamylamylphosphonate in dodecane extraction was investigated. Hexavalent americium was prepared using room-temperature sodium bismuthate oxidation. Under these conditions the majority of the lanthanides were not oxidized and remained inextractable. A separation factor of ～50 was provided for americium from europium over the nitric acid concentration range 6–7 M. Cerium was the exception with oxidation to Ce^IV resulting in its co-extraction with Am^VI. However, since americium is readily reduced to Am^III it was easily stripped with a dilute acidic solution of hydrogen peroxide. Although hydrogen peroxide also reduces cerium, it does so slowly, and a selective americium strip was achieved, with a separation factor of as high as 35. Alternatively, since americium spontaneously reduced in the loaded organic phase, samples allowed to stand for 2 hours could be selectively stripped of americium by contact with 1 M HNO₃ containing no additional reagents. Further, the separation was demonstrated using solutions containing macro-amounts of cerium and americium. The implications for use in fuel cycle separations are discussed.     

Characterizing Diamylamylphosphonate (DAAP) as an Americium Ligand for Nuclear Fuel-Cycle Applications

Successful deployment of the currently-envisioned advanced nuclear fuel cycle requires the development of a partitioning scheme to separate Am from the lanthanides. The Am/lanthanide separation is challenging since all the metals are normally trivalent and have similar ionic radii. Oxidation of Am to higher oxidation states is one option to achieve such a separation. Hexavalent Am has now been routinely prepared in our laboratory in strongly acidic solution using sodium bismuthate as the oxidant, and then extracted into diamylamylphosphonate/dodecane solution. Here, we have characterized this phosphonate-containing solvent with regard to the extraction of Am, the lanthanides, Cm, other fission product, and/or inert constituents expected in dissolved nuclear fuel. Additionally, the effects of irradiation on dispersion numbers and the phosphonate concentration were investigated.