Preparation of ortho-symmetric double (OSD) Z-scheme SnO2\CdSe/ Bi2O3 sonocatalyst by ultrasonic-assisted isoelectric point method for effective degradation of organic pollutants

Siyi Li,Meng Zhang,Xue Ma,Jing Qiao,Hongbo Zhang,Jun Wang,Youtao Song 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.72 No.-

In this work, an ortho-symmetric double (OSD) Z-scheme SnO2\CdSe/Bi2O3 sonocatalyst is skillfullydesigned and synthesized via ultrasonic-assisted isoelectric point method and then the sonocatalyticactivity is studied under ultrasonic irradiation in the degradation of organic contaminants. The effects ofultrasonic irradiation time, sonocatalyst dosage, initial Rhodamine B concentration, organic dye kind andused times are investigated systemically. The formation of OH and h+ are confirmed by using t-BuOH andoxalate, respectively. The Rhodamine B can completely be degraded under given experimental conditionssuch as 10 mg/L Rhodamine B solution, 1.00 g/L OSD Z-scheme SnO2\CdSe/Bi2O3 dosage and 150 minultrasonic process. The formation of mainly intermediate products is studied by Liquid Chromatography–Mass Spectrometry. Moreover, the sonocatalytic reaction mechanism caused by OSD Z-schemeSnO2\CdSe/Bi2O3 is presented.

A highly active Z-scheme NiGa2O4/anthraquinone/MoO3 photocatalyst via charge transfer for sunlight photocatalytic simultaneous conversions of nitrite and sulfite

Xue Ma,Siyi Li,Zhihui Qu,Meng Zhang,Jing Qiao,Xin Cui,Chunquan Wang,Jun Wang,Youtao Song 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.78 No.-

The separation efficiency of photogenerated electron-hole pairs (e –h+) is an important factor for ahighly photocatalytic activity of Z-scheme photocatalytic system. In order to suppress the recombining ofphotogenerated e and h+ and enhance the electron transfer rate, anthraquinone (AQ) as special electrontransfer channel is combined with NiGa2O4 and MoO3, forming a Z-scheme NiGa2O4/AQ/MoO3photocatalyst. Due to unique chemical and physical properties, AQ provides a novel electron transmissionway. Compared with traditional conductive channels (for example, noble metals and graphene), in thisway, the AQ may greatly enhance the electron transfer efficiency. In addition, the related morphology,optical properties and chemical composition were investigated by a sequence of characterizationmethods. The influences of photocatalyst species, irradiation time and used times in simultaneouslyconverting nitrite and sulfite under simulated sunlight were also studied. The results indicate that theprepared Z-scheme NiGa2O4/AQ/MoO3 photocatalyst exhibits a much high activity. The conversion ratesof nitrite and sulfite can reach 89.81% and 94.47%, respectively, under simulated sunlight irradiation forfour hours. The enhanced photocatalytic activity is attributed to the fact that AQ can rapidly transferelectron by inner charge transfer. This charge transfer way can provide a new idea to design subsequentphotocatalysts.

Three narrow band-gap semiconductors modified Z-scheme photocatalysts, Er3+:Y3Al5O12@NiGa2O4/(NiS, CoS2 or MoS2)/Bi2Sn2O7, for enhanced solar-light photocatalytic conversions of nitrite and sulfite

Xue Ma,Chunquan Wang,Guowei Wang,Guanshu Li,Siyi Li,Jun Wang,Youtao Song 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.66 No.-

Three Z-scheme photocatalysts, Er3+:Y3Al5O12@NiGa2O4/NiS/Bi2Sn2O7, Er3+:Y3Al5O12@NiGa2O4/CoS2/Bi2Sn2O7 and Er3+:Y3Al5O12@NiGa2O4/MoS2/Bi2Sn2O7, are designed for synchronous conversions of nitrite and sulfite and fabricated by sol-hydrothermal and calcination methods. In these Z-scheme photocatalysts, three narrow band-gap semiconductors as “conductive ladder” are inserted between Er3+:Y3Al5O12@NiGa2O4 and Bi2Sn2O7 to accelerate the electron transfer from conduction band of Bi2Sn2O7 to valence band of NiGa2O4. Er3+:Y3Al5O12 as an up-conversion luminescence agent (from visible-light to ultraviolet-light) provides enough ultraviolet-light for satisfying the energy demand of wide band-gap NiGa2O4. The prepared photocatalysts are characterized by UV–vis diffuse reflectance spectra (DRS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffractometer (XRD), Fourier transform infrared (FT-IR) spectra and photoluminescence (PL) spectra. The photocatalytic activity of prepared photocatalysts is evaluated via conversions of nitrite and sulfite under simulated solar-light irradiation. The results show that the prepared Er3+:Y3Al5O12@NiGa2O4/NiS/Bi2Sn2O7, Er3+:Y3Al5O12@NiGa2O4/CoS2/Bi2Sn2O7 and Er3+:Y3Al5O12@NiGa2O4/MoS2/Bi2Sn2O7 composites exhibit the high and stable photocatalytic activity during the conversions of nitrite and sulfite. The highest conversion ratios (86.23% and 94.44%) for nitrite and sulfite can be obtained when the Er3+:Y3Al5O12@NiGa2O4/NiS/Bi2Sn2O7 is adopted as photocatalyst under simulated solar-light irradiation. Meanwhile, the effect of simulated solar-light irradiation time and corresponding reaction kinetics on photocatalytic conversions of nitrite and sulfite are also studied. Subsequently, the study of used times shows that the prepared Z-scheme photocatalysts can be effectively reused without an apparent inactivation on photocatalytic activity. These results demonstrate that the Er3+:Y3Al5O12@NiGa2O4/NiS/Bi2Sn2O7 is a potential Z-scheme photocatalyst to be used in actual conversions of nitrite and sulfite under solar-light irradiation.

Effect of Cyclic Deep Cryogenic Treatment on Corrosion Resistance of 7075 Alloy

Ruiming Su,Siyi Ma,Kaining Wang,Guanglong Li,Yingdong Qu,Rongde Li 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.4

The cyclic deep cryogenic treatment was proposed to improve both the hardness and corrosion resistance of the high strength7075 aluminum alloy. The effect of different CDCT times on the exfoliation corrosion and intergranular corrosion of the alloyswere observed by scanning electron microscope. The corrosion behaviors of the alloys were monitored by electrochemicaltechniques. The hardness of the alloy was measured by Vickers hardness tester. Furthermore, the microstructures of thealloys were examined by transmission electron microscope. The results show that the corrosion resistance and hardness arestrongly affected by the precipitate state. The discontinuous grain boundary precipitates and the wide precipitate free zoneswill enhance the corrosion resistance. The fine precipitates distributed evenly in the matrix can increase the hardness. Afterthe CDCT, the corrosion resistance is remarkably improved without sacrificing the hardness. The best combination of thehardness and corrosion resistance is exhibited for the alloy treated with the CDCT twice.

Soft, thin skin-mounted power management systems and their use in wireless thermography

Lee, Jung Woo,Xu, Renxiao,Lee, Seungmin,Jang, Kyung-In,Yang, Yichen,Banks, Anthony,Yu, Ki Jun,Kim, Jeonghyun,Xu, Sheng,Ma, Siyi,Jang, Sung Woo,Won, Phillip,Li, Yuhang,Kim, Bong Hoon,Choe, Jo Young,Huh National Academy of Sciences 2016 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF Vol.113 No.22

<P>Power supply represents a critical challenge in the development of body-integrated electronic technologies. Although recent research establishes an impressive variety of options in energy storage (batteries and supercapacitors) and generation (triboelectric, piezoelectric, thermoelectric, and photovoltaic devices), the modest electrical performance and/or the absence of soft, biocompatible mechanical properties limit their practical use. The results presented here form the basis of soft, skin-compatible means for efficient photovoltaic generation and high-capacity storage of electrical power using dual-junction, compound semiconductor solar cells and chip-scale, rechargeable lithium-ion batteries, respectively. Miniaturized components, deformable interconnects, optimized array layouts, and dual-composition elastomer substrates, superstrates, and encapsulation layers represent key features. Systematic studies of the materials and mechanics identify optimized designs, including unusual configurations that exploit a folded, multilayer construct to improve the functional density without adversely affecting the soft, stretchable characteristics. System-level examples exploit such technologies in fully wireless sensors for precision skin thermography, with capabilities in continuous data logging and local processing, validated through demonstrations on volunteer subjects in various realistic scenarios.</P>