TALANTA
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2019
·
IF 4.916
Y. Ma,A.Y. Chen,X.F. Xie,X.Y. Wang,D. Wang,P. Wang,H.J. Li,J.H. Yang,Y. Li
Element doping is recognized as a powerful way to modify surface defect structure and further enhance the fluorescence performance of graphene quantum dots (GQDs). N-doped, S-doped and S, N co-doped GQDs were synthesized to explore the influence of element doping on fluorescence sensing of dopamine (DA) biomolecules. Two interesting works are found, one is that the N-doped GQDs with urea as N source are more effective than the S-doped and S,N co-doped GQDs, characterized by the higher quantum yield (QY) up to 78% and sensitive fluorescence quenching performance to DA. The other is that the N-doped GQDs with ethylenediamine as N source have the highest QY up to 95%, however, exhibits no quenching performance to DA. This abnormal observation is discussed based on the microstructure analysis. Under the optimal reaction condition, the N-doped GQDs exhibit a dual linear relationship of quenching intensity with DA concentration in the range of 10–3000 nM and 3000–7000 nM with detection limits of 3.3 and 611 nM, respectively. The quenching mechanism of N-doped GQDs toward DA is explored from the view of N chemical states, biomolecule structure of DA homologues and redox reaction of DA.
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RSC Advances
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2019
·Vol. 9
·期 1
·450-459
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IF 3.049
Zhikai Wei,Peng Li,Muhammad Hassan,Pu Wang,Cong Xu,Long-Fei Ren,Yiliang He
Photovoltaic wastewater contains a large amount of thiourea that cannot be directly treated by biological methods because of its biotoxicity. In this study, a novel O3/H2O2 + BiPO4/UV synergy technique was used as a pre-treatment process to degrade thiourea. The effects of H2O2 and catalyst loading were investigated, and the transformation pathway of thiourea was predicted based on the intermediates detected by UPLC-Vion-IMS-QToF. The synergy technique degraded 89.14% thiourea within only 30 min, and complete degradation occurred after 150 min. The TOC removal of O3/H2O2 + BiPO4/UV was 1.8, 1.5, and 1.9 times that of O3/H2O2 and BiPO4/UV/H2O2 single processes and O3/H2O2 + UV process, respectively, which was due to the synergy between H2O2 residues and BiPO4. In addition, thiourea was mainly degraded by ·OH into thiourea dioxide and melamine (polymerized by other intermediates) and then further degraded into biuret and methyl carbamate by the holes of BiPO4, followed by complete mineralization into H2O and CO2. These results confirm that the O3/H2O2 + BiPO4/UV synergy technique is a promising option for the degradation of thiourea.
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ChemCatChem
·
2018
·Vol. 11
·期 4
·1354-1361
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IF 4.674
Xianming Wang,Jianzhi Wang,Xiaoxiao Zhang,Qifeng Tian,Manyu Liu,Ning Cai,Yanan Xue,Weimin Chen,Wei Li,Faquan Yu
Graphical His and HER : Nitrogen doped Cu 2 S/MoS 2 heterojunction nanorod arrays grafted on copper foam in situ have been created for efficient hydrogen evolution reaction. The results showed the remarkably improved catalytic activity by designing and tuning the heterostructure, conductivity and active sites. The fabrication of non-noble element electrocatalysts with comparable catalytic activity with Pt-based materials is in great requirements for water splitting to achieve sustainable hydrogen production. Cu 2 S/MoS 2 heterojunction nanorod arrays on copper foam were prepared for this purpose. The nitrogen doping was achieved in situ. HRTEM, SEM, XPS and EDX verified the heterojunction interfacial texture and the defect-rich nanoarray configuration. The heterojunction interfacial texture, the defect rich configuration and the outward active sites optimized the structure required as a high-efficient hydrogen evolution reaction (HER) electrocatalyst. As a result, the charge transfer resistance of the nanoarrays was estimated to be 5.4 Ω at −200 mV versus RHE, even lower than both the precursors. The electrochemical double layer capacitance was 49.95 mF cm −2 , which was higher than both the precursors. The Cu 2 S/MoS 2 heterojunction nanoarrays-like electrocatalyst exhibited significant performance with a low overpotential (91 mV at 10 mA cm −2 ) and a small Tafel slope (41 mV dec −1 ) in alkaline electrolyte with 85.3 % retained ability after 1000 cycle runs. This work paves a road for developing high-performance HER electrocatalysts.
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ACS Applied Materials & Interfaces
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2018
·
IF 8.097
Wangen Zhao,Fengyang Yu,Shengzhong Frank Liu
The development of Cu2ZnSn(S,Se)4 (CZTSSe) solar cells determines the prospect of thin-film photovoltaic devices because of some of their strengths. However, the usual solution fabrication processes of CZTSSe absorbing layers are either too tedious or highly toxic. Here, we have developed an alternative strategy to prepare kesterite CZTSSe absorber films with a simple and low-toxicity solution process by replacing the commonly employed thiol-based compounds using the glycolic acid aqueous solution, which significantly reduces the environment pollution and toxicity, providing a possibility toward the green solvent process. The power conversion efficiency of 6.81% has been acquired based the aqueous solution-processed CZTSSe thin film via optimizing the fabrication technology.
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APPLIED CATALYSIS B-ENVIRONMENTAL
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2019
·
IF 14.229
Xiaoqing Gao,Shanhui Zhu,Mei Dong,Jianguo Wang,Weibin Fan
Highly efficient synthesis of valuable γ-valerolactone (GVL) by levulinic acid (LA) hydrogenation is still a challenge for Ru-based catalysts under mild condition. In this work, we have reported that ultrathin TiO 2 nanosheets supported Ru nanoparticles showed extraordinarily high catalytic activity, GVL yield (99.1%) and reusability owing to the formation of Ru O Ti interfacial structure. The turnover frequency (TOF) reached as high as 19,045 h −1 at 100 °C, much higher than those of Ru/SiO 2 , Ru/GO, Ru/MoS 2 , and commercial Ru/C. DFT calculation elucidates that the dominant reaction pathway of LA hydrogenation to GVL is preferentially hydrogenated to CH 3 CHOCH 2 CH 2 COOH*, followed by cyclization to CH 3 (OH)C 4 OH 4 OH* (GVL − OH) and final dehydroxylation, irrespective of surface structure. Compared to Ru (0 0 2) facet, Ru/TiO 2 interfacial structure changes the rate-determining step from initial hydrogenation to cyclization, which greatly declines the activation barrier from 0.81 eV to 0.48 eV.
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SOLAR ENERGY
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2019
·
IF 4.674
Shuang Lu,Yinglin Wang,Chunxia Wu,Yichun Liu,Xintong Zhang
Searching for large-scale, non-Pt, efficient counter electrode (CE) materials is still a key challenge to realize the applications of high-performance dye-sensitized solar cells (DSSCs). Herein, we report the spray fabrication of stable, uniform and efficient CoS counter electrode at temperature no higher than 100 °C from CoS nanoparticles prepared by the ultrasonic spray pyrolysis (USP) method. The as-fabricated USP-assisted CoS CEs exhibit comparable electrocatalytic activity to the traditional thermolyzed Pt CE, generating a power conversion efficiency of 8.6% for unoptimized DSSCs. This CoS CEs also exhibited prominent electrochemical and mechanical stability, uniform electrocatalytic activity at the size of 10 × 10 cm, and good bending durability when deposited on flexible ITO/PEN conductive substrates, manifesting the merits of this USP-based strategy for the development of high-performance non-Pt electrocatalysts.
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MICROCHIMICA ACTA
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2019
·Vol. 186
·期 8
·1-8
·
IF 5.479
Quan Yingnan,Yao Jiacheng,Yang Shuo,Chen Lei,Li Jia,Liu Yang,Lang Jihui,Shen He,Wang Yaxin,Wang Yanyan,Yang Jinghai,Gao Ming
A heterojunction microcomposite was synthesized that consists of ZnO nanoparticles (ZnO NPs) anchored on MoS 2 microflowers (MoS 2 MFs). The material is shown to enable trace level detection of the pollutant bisphenol A (BPA). The microcomposite was characterized by XRD, XPS, SEM and TEM. In addition, coupling reaction between phenolic estrogens and Pauly’s reagents was adopted to greatly enhance the SERS signal. BPA display a characteristic Raman band at 1592 cm −1 which can be used for its selective detection. The assay is highly sensitive and has a 1 nM detection limit which is the lowest among the reported semiconductor substrates.
MoS 2 /ZnO MCs SERS substrate broke through the application barrier of semiconductor composite materials in SERS substrates. It also sheds light on a deeper understanding of the charge-transfer based enhancement mechanism.
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Nano-Micro Letters
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2019
·Vol. 11
·期 1
·1-14
·
IF 9.043
Luo Linqu,Song Jianjun,Song Longfei,Zhang Hongchao,Bi Yicheng,Liu Lei,Yin Longwei,Wang Fengyun,Wang Guoxiu
3D hierarchical conductive Sn quantum dots encapsulated in N,S co-doped carbon nanofibers sheathed within rGO scrolls (Sn/NS-CNFs@rGO) were prepared through an electrospinning process.
Flexible Sn/NS-CNFs@rGO electrode exhibits superior long-term cycling stability and high-rate capability in sodium-ion batteries.
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DALTON TRANSACTIONS
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2019
·Vol. 48
·期 35
·13176-13183
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IF 4.052
Lang Pei,Yongjun Yuan,Jiasong Zhong,Taozhu Li,Tao Yang,Shicheng Yan,Zhenguo Ji,Zhigang Zou
Tantalum nitride (Ta3N5) with an appealing band gap (∼2.1 eV) has emerged as a promising catalyst in the photocatalysis field. However, Ta3N5 application in the photocatalytic hydrogen evolution reaction (HER) is limited due to disadvantages such as unsatisfactory separation and transfer of photogenerated carriers. Here we utilize MoS2 as co-catalysts to promote the kinetics of photocatalytic H2 evolution over Ta3N5. The Ta3N5 nanorods were encapsulated into 3D hydrangea-like MoS2 for maximizing the contact areas between Ta3N5 and MoS2 and offering rich active sites. More importantly, spectroscopic analysis and theoretical calculations consistently reveal that the unique interfacial interaction, as well as the matching band alignment between Ta3N5 and MoS2, accelerates the photogenerated charge extraction from Ta3N5 to MoS2, reducing charge recombination losses in Ta3N5. Thus, the optimized Ta3N5/MoS2 hybrid exhibits a substantially enhanced hydrogen evolution rate (56.5 μmol h−1), over 22 times higher than that of pristine Ta3N5. This work may provide a general strategy to overcome the low photocatalytic activity of nitrides for hydrogen evolution.
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ACS Sustainable Chemistry & Engineering
·
2019
·
IF 6.97
Mancong Li,Yongteng Qian,Jimin Du,Haoran Wu,Linyu Zhang,Gang Li,Kaidi Li,Weimin Wang,Dae Joon Kang
The design and fabrication of eco-friendly, highly efficient, and non-noble-metal-based catalysts are demanding challenges in energy-conversion technologies. Herein, we successfully synthesized CuS nanosheets decorated with CoS2 nanoparticles through a facile route. The optimized 3% CoS2-7% CuS catalysts exhibited remarkable electrocatalytic performance, with excellent cyclic stability at all pH values for the hydrogen evolution reaction (HER). They exhibited lower Tafel slopes (46, 52, and 59 mV dec–1) and smaller overpotentials (62, 85, and 106 mV) at 10 mA cm–2 in 0.5 M H2SO4, 1 M KOH, and 0.5 phosphate buffer aqueous solutions, respectively, than other CoS2/CuS, pure CoS2, and pure CuS catalysts. We attribute their high electrocatalytic performance to their unique heterostructure and the synergistic effects between the constituent metal sulfides that provides a large interfacial contact area, numerous charge-transfer pathways, as well as abundant surface reaction active sites, enhancing the charge-carrier transfer during the HER activity.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2019
·
IF 4.175
N’dri Dieudonné Diby,Yueqin Duan,Patrick Atheba Grah,Fengshi Cai,Zhihao Yuan
In the photoelectrochemical (PEC) water splitting for the hydrogen production, the fabrication of a stable and efficient photocatalyst semiconductor remains a challenge. CdS, which is one of most used chalcogenide materials, coupled with metal oxide semiconductor exhibit a generally low durability. TiO 2 nanorods arrays (TNR) sensitized with CdS were synthesized via hydrothermal method and denoted as TNR-CdS. CdS deposition on TNR surface was controlled by regulating the hydrothermal reaction time. The samples were characterized by X-ray diffraction, Raman spectroscopy , scanning electronmicroscopy, X-ray photoelectron spectroscopy, and UV-visible absorption. A high PEC performance as well as a great CdS sensitized TNR photoanodes stability were exhibited. These results could be due to the intimate contact between CdS and TNR, favoring a fast separation of photogenerated charge carriers. The optimal PEC performance was achieved when CdS was deposited on TNR for 10 h. Under AM 1.5G illumination at applied potential of 0 V vs Ag/AgCl, TNR-CdS (10 h) is found to have a photocurrent density of 6.5 mA/cm 2 against 2.25 mA/cm 2 for TNR. Additionally, TNR-CdS (10 h) presented a photoconversion efficiency of 2.5% at −0.4 V vs Ag/AgCl, while that of TNR was 0.9% at-0.35 V vs Ag/AgCl. TNR-CdS showed great stability with and without sacrificial reagent. These results were confirmed by electrochemical impedance spectroscopy measurements, where the rapid transfer/transport and separation of photogenerated charge carriers were highlighted.
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Journal of Energy Chemistry
·
2019
·
IF 5.162
Biwen Duan,Linbao Guo,Qing Yu,Jiangjian Shi,Huijue Wu,Yanhong Luo,Dongmei Li,Sixin Wu,Zhi Zheng,Qingbo Meng
In CZTSSe solar cells, a simple sodium-incorporation post-treatment method toward solution-processed Cu 2 ZnSnS 4 precursor films is presented in this work. An ultrathin NaCl film is deposited on Cu 2 ZnSnS 4 precursor films by spin-coating NaCl solution. In subsequent selenization process, the introduction of NaCl is found to be benefacial for the formation of Cu 2- x Se, which can further facilitate the element transportation, leading to dense and smooth CZTSSe films with large grains and less impurity Cu 2 Sn(S,Se) 3 phase. SIMS depth profiles confirm the gradient distribution of the sodium element in Na-doped absorbers. Photoluminescence spectra show that the introduction of appropriate sodium into the absorber can inhibit the band tail states. As high as 11.18% of power conversion efficiency (PCE) is achieved for the device treated with 5 mg mL −1 NaCl solution, and an average efficiency of Na-doped devices is 10.71%, 13% higher than that of the control groups (9.45%). Besides, the depletion width and the charge recombination lifetime can also have regular variation with sodium treatment. This work offers an easy modification method for high-quality Na-doped CZTSSe films and high-performance devices, in the meantime, it can also help to further understand the effects of sodium in CZTSSe solar cells.
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