Well-construction of Zn_(2)SnO_(4)/SnO_(2)@ZIF-8 core-shell hetero-structure with efficient photocatalytic activity towards tetracycline under restricted space

Nowadays,efficient removal of antibiotic(e.g.tetracycline,TC) from water bodies has been of great global concern.Hereby,a novel Zn_(2)SnO_(4)/SnO_(2)@ZIF-8 photo-catalyst was first synthesized by a facile selfassembly in-situ growth method.Zn_(2)SnO_(4)/SnO_(2)@ZIF-8 exhibits a remarkable photocatalytic activity towards TC under visible-light driven with a rapid rate constant of 1.5 × 10^(-2)min^(-1), and a removal efficiency of 81.2%,which is superior to some catalysts in the literature.Importantly,the photocatalytic activity of Zn_(2)SnO_(4)/SnO_(2)@ZIF-8 could still remain ~77% after the fifth cycle,indicating its good stability and reusability.The remarkable performances of adsorption and photocatalytic were attributed to associative effects of catalytic activity of Zn_(2)SnO_(4)/SnO_(2)and the unique porous nanostructure and stability of ZIF-8.This work could aid the future design and preparation of novel MOFs composite catalysts for efficient elimination of antibiotics from water.

Effects of interfacial wettability on arc erosion behavior of Zn_(2)SnO_(4)/Cu electrical contacts

Interface wettability is a vital role in directly impacting the electrical contact characteristics of oxides/Cubased composites under arc erosion.Exploring its influence mechanism,especially at atomic/electronic scales,is significant but challenging for the rational design of oxides/Cu contacts.Here,we designed Zn_(2)SnO_(4)/Cu electrical contacts aiming to solve the poor wettability of SnO_(2)/Cu composites.It was found that Zn_(2)SnO_(4)could remarkably improve the arc resistance of Cu-based electrical contacts,which was benefited by the excellent interface wettability of Zn_(2)SnO_(4)/Cu.The characterization of eroded surface indicated that Zn_(2)SnO_(4)particles distributed uniformly on the contact surface,leading to stable electrical contact characteristic.Nevertheless,SnO_(2)considerably deteriorated the arc resistance of SnO_(2)/Cu composite by agglomerating on the surface.The effect mechanism of wettability on arc resistance was investigated through density function theory(DFT)study.It revealed that strong polar covalent bonds across the Zn_(2)SnO_(4)/Cu interface contributed to improving the interfacial adhesion strength/wettability and thus significantly enhanced the arc resistance.For binary SnO_(2)/Cu interface,ionic bonds resulted in weak interface adhesion,giving rise to deterioration of electrical contact characteristic.This work discloses the bonding mechanism of oxide/Cu interfaces and paves an avenue for the rational design of ternary oxide/Cu-based electrical contact materials.

Solvothermal growth of Zn_(2)SnO_(4) for efficient dye-sensitized solar cells

Zn_(2)SnO_(4)plates,particles and spheres are suc-cessfully prepared via a facile synthesis way by carefully adjusting the solvothermal conditions,which are further applied as photoanodes in dye-sensitized solar cells(DSSCs)to explore the relationships between the pho-toanode nanostructure and the photovoltaic performances.As a result,the DSSCs based on Zn_(2)SnO_(4)spheres pho-toanode showcased the best power conversion efficiency(PCE,4.85%),compared to Zn_(2)SnO_(4)plates(3.80%)and particles(4.13%).It is found that Zn_(2)SnO_(4)spheres exhibit the highest light-scattering abilities,as evidenced by ultraviolet–visible(UV–Vis)diffuse reflectance spectra.Additionally,investigations on dynamic electron transport and recombination properties via intensity-modulated photovoltage/photocurrent spectroscopy(IMVS/IMPS),and electrochemical impedance spectroscopy(EIS)mea-surements demonstrate that the Zn_(2)SnO_(4)spheres-based DSSCs possess the fastest electron transport rate,the longest electron lifetime,the highest electron collection efficiency(ηc c),and the largest charge recombination resistance,compared with the Zn_(2)SnO_(4)plates and particles,all of which are highly beneficial for the powder conversion efficiency enhancements.

An ultrafast carrier dynamics system from oxygen vacancies modified SnO_(2)QDs and Zn_(2)SnO_(4)heterojunction for deeply photocatalytic oxidation of NO

Deeply photocatalytic oxidation of NO-to-NO_(3)holds great promise for alleviating NO_(x) pollution.The major challenge of NO photo-oxidation is the highly in-situ generated NO_(2) concentration,and the formation of unstable nitrate species causes desorption to release NO_(2).In this study,SnO_(2) quantum dots and oxygen vacancies co-modified Zn_(2)SnO_(4)(ZSO-SnO_(2)-OVs)were prepared by a one-step hydrothermal procedure,the NO photo-oxidation was investigated by a combination of solid experimental and theoretical support.Impressively,spectroscopic measurements indicate that fast carrier dynamics can be achieved due to the electron transfer efficiency of ZSO-SnO_(2)-OVs reaching 99.99%,far outperforming the counterpart and previously reported photocatalysts.During NO oxidation,molecular NO/O_(2) and H2O are efficiently adsorbed/activated around OVs and SnO_(2) QDs,respectively.In-situ infrared measurements and calculated electron localized function disclose two main findings:(1)richly electrons enable NO promptly form NOinstead of toxic NO_(2) or NO^(+);(2)the generation of stable and undecomposed bidentate NO_(3)rather than bridging or monodentate one benefits the deep oxidation of NO via shifting reaction sites from O terminals for original ZSO to Sn ones for ZSO-SnO_(2)-OVs.The synergistic action of SnO_(2) QDs and OVs positively contributes to the NO oxidation performance enhancement(60.6%,0.1 g of sample)and high selectivity of NO to NO_(3)(99.2%).Results from this study advance the mechanistic understanding of NO photooxidation and its selectivity to NO_(3)over photocatalysts.

Inverted polymer solar cells with Zn_2SnO_4 nanoparticles as the electron extraction layer

In this study, we report narrow-size distribution Zn_2SnO_4（ZSO） nanoparticles, which are produced by low-temperature solution-processed used as the electron extraction layer（EEL） in the inverted polymer solar cells（i-PSCs）. Moreover, poly[（9,9-bis（30-（N,N-dimethylamino）propyl）-2,7-fluorene）-alt-2,7-（9,9-dioctylfluorene）]（PFN） is used to modify the surface properties of ZSO thin film. By using the ZSO NPs/PFN as the EEL, the i-PSCs fabricated by poly[4,8-bis（2-ethylhexyloxyl）benzo[1,2-b：4,5-b0] dithio-phene-2,6-diyl-altethylhexyl-3-fluorothithieno [3,4-b]thiophene-2-carboxylate-4,6-diyl]（PTB7） blended with（6,6）-phenyl-C_（71）-butyric acid methylester（PC_（71）BM） bulk heterojunction（BHJ） composite, exhibits a power conversion efficiency（PCE） of 8.44%, which is nearly 10% enhancement as compared with that of7.75% observed from the i-PSCs by PTB7：PC_（71）BM BHJ composite using the ZnO/PFN EEL. The enhanced PCE is originated from improved interfacial contact between the EEL with BHJ active layer and good energy level alignment between BHJ active layer and the EEL. Our results indicate that we provide a simple way to boost efficiency of i-PSCs.

锡酸锌基光催化材料研究进展

在各类半导体光催化材料中,反尖晶石结构的锡酸锌(Zn_(2)SnO_(4))因传导率良好、电子迁移率高、物化性质稳定且无毒而成为研究热点。近年来,随着研究的不断深入,人们采用(微波)水热法合成出具有不同形貌结构的Zn_(2)SnO_(4)。但因合成条件对Zn_(2)SnO_(4)形貌的影响很大,且缺乏系统性总结,因而本文概述了(微波)水热合成方法中水热时间、合成温度以及原材料、矿化剂与表面活性剂类型和浓度对Zn_(2)SnO_(4)晶体构型、表面电子结构、形貌特征、粒径尺寸及催化性能的影响,以期指导Zn_(2)SnO_(4)特定形貌的可控合成。此外,本文还介绍了提升Zn_(2)SnO_(4)光催化活性的改性策略,即元素掺杂、构建异质结、单质负载(贵金属沉积)、形貌调控和缺陷工程,系统总结了各种改性策略对能带结构、光吸收、光生载流子分离迁移、表面催化反应和光催化性能的影响。最后,展望了Zn_(2)SnO_(4)基半导体光催化材料在各类光催化应用中所面临的挑战与机遇。