Journal of Materials Chemistry A
·
2020
·Vol. 8
·期 42
·22292-22301
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IF 11.301
Junjie Fu,Dongxing Kou,Wenhui Zhou,Zhengji Zhou,Shengjie Yuan,Yafang Qi,Sixin Wu
A major obstacle hindering further development of kesterite Cu2ZnSn(S,Se)4 (CZTSSe) solar cells is the inherent recombination losses that occur both via bulk defects and charge extraction interfaces. Herein, we propose a generic Ag, Ge dual-gradient absorber architecture, involving a downshift of absorber VBM at the front contact and an upshift of absorber CBM at the back contact, to improve device performance. We experimentally show that the substitution of Cu by Ag allows for larger band bending at the p–n junction, and the substitution of Sn by Ge imposes an additional drift field within the quasi-neutral region. Additionally, the Ag and Ge ions diffusing into the bulk absorber passivate the deleterious CuZn and CuSn deep-level defects. In turn, accelerated charge extraction, transport and minimized recombination loss offered surprising gains in Voc and Jsc, and the dual-gradient device achieved a maximum efficiency of 12.26% with an improved Voc,deficit of 553 mV. This Ag, Ge graded-substitution approach offers an alternative absorber architecture to improve the Voc,deficit in future high-efficiency kesterite PV cells.
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Journal of Materiomics
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2015
·
IF 0
Junwei Fu,Shaowen Cao,Jiaguo Yu
Photocatalytic hydrogen generation is one of the most promising solutions to convert solar power into green chemical energy. In this work, a multi-component TiO 2 –Ag–Cu 2 O composite was obtained through simple impregnation-calcination of Cu 2 O and subsequent photodeposition of Ag onto electrospun TiO 2 nanotubes. The resulting TiO 2 –Ag–Cu 2 O photocatalyst exhibits excellent photocatalytic H 2 evolution activity due to the synergetic effect of Ag and Cu 2 O on electrospun TiO 2 nanotubes. A dual Z-scheme charge transfer pathway for photocatalytic reactions over TiO 2 –Ag–Cu 2 O composite was proposed and discussed. This work provides a prototype for designing Z-scheme photocatalyst with Ag as an electron mediator.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2020
·
IF 7.489
Xiaodong Zhang,Liang Song,Fukun Bi,Dongfeng Zhang,Yuxin Wang,Lifeng Cui
In this paper, dispersed Ag nanoparticles supported on UiO-66 derivative were prepared and the effect of Ag loading on the structure and performance of the catalysts for toluene oxidation were studied. The characteristics of the catalysts were studied by XRD, SEM, TEM, HRTEM, BET, ICP-OES, XPS, UV–vis and in situ DRIFTS. It was observed that UiO-66 structure of 2 wt% Ag catalyst (2Ag-U) was not damaged. When Ag loading was further increased to 10 wt% (10Ag-U), framework of UiO-66 collapsed and uniform Ag nanoparticles were dispersed on the surface of support. Further increasing Ag to 14 wt% (14Ag-U), large Ag nanoparticles were observed, and Ag species migrated to the bulk phase of the support, resulting in the decrease of surface Ag content. The 10Ag-U catalyst showed excellent catalytic performance due to higher lattice oxygen and surface Ag 0 content. In addition, in situ DRIFTS analysis was used to explore toluene-catalyzed intermediates. It was found that toluene was converted to benzaldehyde and benzoic acid, eventually forming CO 2 and H 2 O.
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MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
·
2021
·
IF 3.927
Xiao Tian,Jiaxiong Xu
The reported Ag and Mn co-doped Cu 2 ZnSnS 4 thin film has better properties than single-doped Cu 2 ZnSnS 4 . However, the role of Mn in co-doped Cu 2 ZnSnS 4 thin film is still unclear. In this paper, Ag and Mn co-doped Cu 2 ZnSnS 4 thin films with different Mn amounts were prepared by sol-gel method. The crystal phases, morphologies, element compositions, and optical properties of co-doped Cu 2 ZnSnS 4 thin films were characterized to investigate the role of Mn doping. Compared with Ag single-doped Cu 2 ZnSnS 4 thin film, after the incorporation of Mn into Ag-doped Cu 2 ZnSnS 4 , the crystallinity of Cu 2 ZnSnS 4 improves and the micro-strain and dislocation density in the crystal reduce. The valence states of Cu, Zn, Sn, S, Ag, and Mn in co-doped thin film are +1, +2, +4, −2, +1, and +2, respectively. Mn doping can make the grains on the thin film surface enlarge. The MoS 2 interface layer between Cu 2 ZnSnS 4 and Mo becomes thinner and the Urbach energy of Cu 2 ZnSnS 4 decreases after Mn doping. Therefore, Mn in the co-doped Cu 2 ZnSnS 4 thin films shows beneficial effects of enhanced structural, morphological, and optical properties of the films.
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SENSORS AND ACTUATORS B-CHEMICAL
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2021
·
IF 7.46
Chengyu Yang,Ying Yang,Chengxin Zhang,Hui Yu,Tingting Wang,Keying Shi,Zhuanfang Zhang,Dongjie Wang,Xiangting Dong
In this paper, a simple method to synthesize Ag-doped Fe 2 O 3 hollow nanofibers by electrospinning was reported. The synthesized samples were fabricated into gas sensors, and their sensing properties were studied systematically. The results showed that the Ag-doped Fe 2 O 3 materials were hollow tubular structures and had high response (R a /R g = 19.43), selectivity and sensitivity to H 2 S at room temperature. The response mechanism of the sensor to H 2 S was studied by DFT, O 2 -TPD and H 2 -TPR. It was considered that the excellent gas sensing performance of the sensor was that the Ag-dopant increased the concentration of carriers, adsorbed oxygen and lattice oxygen. The rough hollow structure was conducive to gas adsorption and capture, which provided many active centers for the sensing reaction. Therefore, the Ag-doped Fe 2 O 3 nanofibers with hollow structure will have promising uses as sensing material in future applications.
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MICROPOROUS AND MESOPOROUS MATERIALS
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2016
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IF 3.349
Mingming Zou,Honghong Liu,Lu Feng,Fengqiang Xiong,Tiju Thomas,Minghui Yang
A simple solvothermal approach with post-calcination is used to obtain (Ag, Ag 2 O) co-loaded TiO 2 microspheres with high specific surface area (43.8 m 2 g -1 ) and desirable visible light photocatalytic degradation (64% after 2 h visible light irradiation). Generally, N-doping of TiO 2 via nitridation using NH 3 improves the visible light absorption property of material. However, nitridation of (Ag, Ag 2 O) co-loaded TiO 2 results in a deleterious impact on the photocatalytic performance (around 20% after 2 h visible light irradiation). This is because nitridation of Ag-Ag 2 O-TiO 2 results in (a) reduction of Ag 2 O to Ag and (b) Ag agglomeration and grain growth on TiO 2 particles. These results in fact imply that in as-synthesized (Ag, Ag 2 O) co-loaded TiO 2 systems, local surface plasmonic resonance (associated with of 5–12 nm Ag particles) aids in enhanced broad band visible light absorption; furthermore the heterojunction between TiO 2 and Ag 2 O improves efficiency with which photogenerated carriers become available for photocatalysis . In all cases we show through selective radical quenching experiments that singlet oxygen is the primary reason for the dye degradation observed.
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Materials
·
2015
·Vol. 8
·期 5
·2043-2053
·
IF 2.651
Xiyun Zhao,Jie Zhang,Binsong Wang,Amir Zada,Muhammad Humayun
Photocatalytic removal of organic pollution such as waste colored dyes was a promising technique for environment technique. However, effective photocatalysts were needed to enhance the photocatalytic efficiency. Ag/AgCl was regarded as high performance catalyst for photocatalytic degradation. Ag/AgCl nanoparticles were biochemically prepared with metabolin of living fungi which was used as reductant and characterized by X-Ray diffraction (XRD), UV-visible spectroscopy and transmission electron microscopy (TEM). The Ag/AgCl nanoparticle composites showed spherical aggregation shape with an average size of about 3–5 nm which is well inside the quantum regime. The UV-visible study showed that Ag/AgCl nanoparticles had strong visible light absorption and exhibited excellent visible-light-driven photocatalytic performance. Photocatalytic results indicated that the obtained Ag/AgCl nanoparticles were suitable for photocatalytic removal of RhB dye under visible light irradiation. The excellent photocatalytic activities could be attributed to the quantum size nanoparticles and the Plasmon resonance of Ag/AgCl composites.
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Nano Energy
·
2020
·
IF 16.602
Cijun Shuai,Guofeng Liu,Youwen Yang,Fangwei Qi,Shuping Peng,Wenjing Yang,Chongxian He,Guoyong Wang,Guowen Qian
Polyvinylidene fluoride (PVDF)/barium titanate (BaTiO 3 ) composites are becoming increasingly attractive in bone repair since it combines the advantage of polymer flexibility and ceramic piezoelectric constant. Herein, silver (Ag) nanoparticles were decorated on polydopamine functioned BaTiO 3 (Ag-pBT) by in situ growth. Then the strawberry-like structured Ag-pBT nanoparticles were introduced into PVDF scaffold fabricated by selective laser sintering . On one hand, Ag nanoparticles would act as a conductive phase to enhance the strength of the polarized electric field on BaTiO 3 , thereby forcing more domains to be aligned in the direction of the electric field and make piezoelectric effect of BaTiO 3 fully play in composite scaffold . On the other hand, Ag nanoparticles would attack multiple targets in bacteria by release of Ag + and production of reactive oxygen species. In fact, the antibacterial activity is highly desirable for bone repair. Results demonstrated that the PVDF/4Ag-pBT scaffold exhibited enhanced piezoelectric properties with output current and voltage increased by 50% and 40% than that of PVDF/pBT, respectively. In vitro cell culture confirmed that the enhanced electric output further promoted cell proliferation and differentiation. Meanwhile, the scaffold presented robust antibacterial activity against E.coli.
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CERAMICS INTERNATIONAL
·
2021
·
IF 4.527
Wenjing Yang,Xuan Chen,Xun Yuan,Jia Yao,Weiliang Cai,Shuping Peng,Cijun Shuai
A novel design of antibacterial and magnetic halloysite nanotubes loaded with Ag and Fe 3 O 4 was reported. In detail, magnetic nanoparticles (Fe 3 O 4 ) were immobilized on the surface of halloysite nanotubes (HNTs) via electrostatic adsorption (termed as HNTs/Fe 3 O 4 ). The magnetic HNTs/Fe 3 O 4 was then modified by polydopamine to in-situ grow Ag nanoparticles by a redox reaction , forming a composite nanostructure of HNTs/Fe 3 O 4 @Ag. The HNTs/Fe 3 O 4 @Ag was incorporated into poly- l -lactic acid (PLLA) scaffold fabricated via selective laser sintering , with the intent to endow the scaffold with robust antibacterial function and favorable cell activity. The results showed that the released Ag + from the scaffold significantly against E. coli activity, with bacterial inhibition rate above 99%. Moreover, ion release behavior showed a scaffold enable to sustain release Ag + over 28 days. Furthermore, Fe 3 O 4 nanoparticles constructed magnetic microenvironment greatly enhanced cell activity and promoted cell proliferation . In addition, tensile strength of the scaffold increased by 52.9% compared with PLLA scaffold. These positive results suggested that the HNTs/Fe 3 O 4 @Ag nanostructure possessed potential in facilitating bone repair.
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JOURNAL OF ALLOYS AND COMPOUNDS
·
2021
·
IF 5.316
Wenqian Yan,Kunmeng Zhu,Yi Cui,Yanhan Li,Tao Dai,Sheng Cui,Xiaodong Shen
A new material of Ag-SnO 2 /rGO aerogel is fabricated by the sol-gel method and freeze-drying technique. The SnO 2 particles are tightly arranged on the rGO sheets to form a p-n heterojunction , and the rGO aerogel possesses abundant pore structures for effective adsorption. Besides, the Ag particles are dispersed on the surface as a catalyst to improve the internal electron mobility, further promoting the gas-sensing performance. To be noted, the Ag-SnO 2 /rGO aerogel can exhibit a response of 2.13 towards 50 ppm NO 2 at RT instead of heating conditions, and shows a cyclic capacitance property of redox. Moreover, the non-linear growth between gas concentration and response is observed, which proves the chemical adsorption that results in the high selectivity.
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ACS Applied Nano Materials
·
2022
·
IF 6.14
Xue Wang,Li-Yuan Wang,Cheng-Bao Yao,Ze-Miao Wang,Yu Liu,Cai-Hong Jiang
The metal/metal oxide semiconductor materials with special photoelectric properties have been widely used for the development of novel photoelectric devices. However, electron transfers at the interfaces of metal and metal oxide are unclear under a photoexcitation process. Herein, the pure WO3 nanorods and Ag nanoparticles (NPs)-loaded WO3 (AWO) nanorods were synthesized by a hydrothermal technique and a two-step method, which includes hydrothermal and magnetron processes. Their corresponding electron excitation and relaxation properties have been revealed by absorption/emission spectra and transmission curves under nonlinear excitation of an ultrafast laser. The dependence relationship for the morphology and structure of one-dimensional (1D) WO3 nanomaterial orientation on the parameters’ adjustment (reaction time and reactant concentration) and formation mechanism was studied. The 1D WO3 nanomaterials show obvious longitudinal growth in the (200) orientation, as well as lateral growth in the (001) and (110) orientations. The size and distribution effects of Ag NPs on the optical properties of WO3 have also been investigated. On the basis of quantum particle coupling between metal (Ag) and metal oxide materials (WO3 nanorods), electron–hole pairs were generated in the semiconductor and strongly enhanced the radiative recombination. The Z-scan results illustrated that the maximum nonlinear absorption coefficient of the AWO (6 W) nanorods was obtained. When charge transfer happens in Ag NPs, the density of the electronic states in the excited/defect states of the WO3 can be regulated. For AWO nanorods, the ground state of Ag undergoes a saturation absorption process and results in reverse saturation absorption of the excited/defect states. Because of their remarkable nonlinear-optical properties, the proposed AWO nanorods will be potential nanocomposite materials for the development of nonlinear absorption modulator devices.
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Journal of Physical Chemistry C
·
2021
·
IF 4.126
Weiyu Wang,Qiang Wang,Yueying Chu,Guodong Qi,Shenhui Li,Jun Xu,Feng Deng
Alkyne semihydrogenation offers a key approach for the synthesis of stereodefined molecules. The stereoselective hydrogenation of propyne to propene over Al2O3-supported Pd–Ag bimetallic catalysts is studied by using parahydrogen-induced polarization (PHIP) NMR technique. The supported catalysts were prepared by an incipient-wetness impregnation method, and their properties were systemically tuned by altering Pd and Ag components. Structural characterization by X-ray diffraction, infrared spectra, and transmission electron microscope shows the formation of highly dispersed bimetallic Pd–Ag nanoparticles with random alloy structures on Al2O3 support. For the hydrogenation of propyne over Pd–Ag catalysts with higher Ag concentration, the adsorbed protons are mostly restricted on the active Pd ensembles, which favors a higher pairwise hydrogen addition to propyne, leading to a stronger PHIP effect. The product stereoselectivity measurements show that the pairwise syn-addition to propyne increases with Ag content in the Pd–Ag alloy. The reaction conditions impact the pairwise hydrogenation stereoselectivity. A lower H2/propyne ratio of reactant flow or a higher total reactant flow rate enhances the apparent pairwise syn-addition stereoselectivity, which can be accounted for by the suppressed cis–trans isomerization process and/or a higher intrinsic pairwise syn-addition selectivity.
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