查找使用阿拉丁产品的科研文献

A topological chemical transition strategy of bismuth-based materials for high-efficiency electrocatalytic carbon dioxide conversion to formate

Runze Ye,Yun Tong,Dongmei Feng,Pengzuo Chen

The electrochemical reduction of carbon dioxide (ERCO2) to formate with high selectivity has been considered a promising strategy to overcome the energy and environmental crises. Bi-based materials present good application prospects, but the development of a new class of electrocatalysts with high performance remains a challenge. Herein, a novel topological chemical transition strategy is developed to rationally design highly active Bi-based materials, which are a new representative of Bi-based electrocatalysts for ERCO2. Bismuth oxysulfate (Bi2O2SO4) is prepared by a simple topological transition from the Bi2S3 precursor in air, which can further topologically transform into the metal Bi by a fast reduction treatment of NaBH4 solution. This kind of Bi2O2SO4 exhibits superior catalytic performance for ERCO2. The maximum Faraday efficiency (FE) of HCOO− is up to 97% at −0.9 V vs. RHE in an H-type cell. A high FE > 90% in a wide potential range of −0.5 to −1.2 V and a large current density of 319 mA cm−2 at −0.8 V can further be realized in a flow cell. The post-characterization studies and density functional theory (DFT) calculations confirm that the Bi2O2SO4 derived Bi catalyst has an optimal (104) plane to realize the optimized free energies of OCHO* and H* reaction intermediates, leading to superior catalytic activity over the NaBH4 derived Bi sample. Our work put forward a promising strategy to exploit advanced electrocatalysts for electrolysis.

ZnPc/CsPbBr3 QDs collaborative interface modification to improve the performance of CsPbBr3 perovskite solar cells

Li Zou,Xiaoyan Li,Meili Yang,Jiahao Yan,Jiaming Wang,Jiajie Cheng,Jie Xing,Hao Liu,Huiying Hao,Jingjing Dong

Carbon-based, all-inorganic CsPbBr 3 perovskite solar cells (PSCs) have attracted considerable interests because of their superior environmental stability, simple and low-cost fabrication process. However, the large energy barrier and high defect states at the CsPbBr 3 /Carbon interface will cause poor carrier extraction and serious carrier recombination, which further degrade performance of final devices. In this work, we introduce zinc phthalocyanine (ZnPc), CsPbBr 3 quantum dots (QDs), and ZnPc mixed CsPbBr 3 QDs in proper proportion as the CsPbBr 3 /carbon interface modification layers of CsPbBr 3 PSCs. It is found that the modification layers, especially the ZnPc mixed CsPbBr 3 QDs modification layer, can passivate trap states, improve interface contact and optimize energy level alignment at the CsPbBr 3 /carbon interface, which can further enhance carrier extraction, suppress carrier recombination and improve performance of final devices. By virtue of ZnPc mixed CsPbBr 3 QDs modification, a highest efficiency of 10.20% and long-term stability over 6 months has been achieved.

Synergistic Effects of Surface Ligand Engineering and Double Matrices Protecting Enable Ultrastable and Highly Emissive Blue/Cyan Perovskite Nanocrystal Films for Multifunctional Applications

Xiaobo Hu,Yanqiao Xu,Jiancheng Wang,Jiaxin Ma,Lianjun Wang,Wan Jiang

Perovskite nanocrystals (NCs) have attracted considerable attention because of the extraordinary optoelectronic properties, making them promising candidates for lighting and display applications. However, the emissive efficiency and stability of blue/cyan-emitting NCs lag far behind other color emissive perovskites, which greatly restrict their practical application. Herein, a feasible strategy is proposed for synthesizing highly luminescent and stable CsPbCl x Br 3− x NCs by the didodecyldimethylammonium bromide (DDAB) ligand-assisted post-treatment. The prepared DDAB-CsPbCl 0.8 Br 2.2 and DDAB-CsPbCl 2.0 Br 1.0 NCs exhibit bright cyan and blue emission, respectively, and their quantum yields are significantly enhanced from 12.2% and 7.5% to 83.1% and 75.3% owing to the obvious decrease of surface defects by the ligand-exchange and halogen-compensation mechanisms. The outstanding fluorescence properties are almost remained by grafting perovskite NCs onto the surface of SiO 2 nanospheres. Notably, the ultrahigh water-stability is realized after encapsulating the composite nanospheres into polystyrene-polyisoprene-polystyrene (SIS) film, which is benefit from the triple protection of DDA + cations, SiO 2 nanospheres and SIS copolymers. The fabricated SiO 2 @DDAB-CsPbCl 2.0 Br 1.0 /SIS film is assembled into an white light emitting diode with high color rendering index of 83.4. Importantly, the blue/cyan-emitting films display superb temperature-sensitivity (30–160 °C) and favorable elasticity (1200% stretch rate), indicating their promising application prospect in flexible multifunctional photoelectric devices.

Effect of Different Ligands Coating on the Photovoltaic Performance of CdSe Quantum Dot-Sensitized Solar Cells

Yexin Chen,Shibing Zou,Wenhua Zou,Dongyang Wang,Junhong Duan,Weiqing Liu,Huaming Wu

Modified Ni Nanoparticles as Additives in Various Greases: Assessment of Comparative Performance Potential

Jiabei Wang,Hong Zhang,Wenjing Hu,Jiusheng Li

China’s rapid industrial development requires more energy consumption based on non-renewable energy resources. The energy consumption caused by unnecessary friction accounts for about 4.5% of the GDP in China. Although grease effectively lubricates machines, lubrication failure may occur under severe conditions. Nanomaterials exhibit intriguing tribological performances and have received much attention regarding lubrication. In this study, oleylamine-modified Ni nanoparticles (OA-Ni) were synthesized and used as lubricant additive in four kinds of commonly used greases: lithium, calcium, composite calcium, and polyurea grease. The OA-Ni were uniformly dispersed in the greases through electromagnetic stirring, ultrasonic vibration, and three-roll grinding. The physicochemical properties and the structure of OA-Ni-doped grease were investigated, while the feasibility of OA-Ni as various grease additives at different contact modes was evaluated by a four-ball friction tester and a UMT-tribolab tester. Tribological tests results revealed that the friction-reducing and anti-wear properties of point-to-point contact were increased by 56.7% and 70.3% in lithium grease, respectively, while those of the point-to-face contact were increased by 59.5% and 68.9% in polyurea grease, respectively. The present work provides not only theoretical guidance of nano nickel modification but also a practical reference for the application of modified nanomaterials to various greases.Keywords:nano-lubrication;modified nanomaterial;multiple greases;tribological properties

Direct conversion of water to hydrogen peroxide on single electrode towards partial oxidation of propylene

Runfei Xu,Haoyang Huang,Wenjing Wang,Lei Ding,Qiang Lin,Jinbing Li,Yu Zhang,Yongsheng Han,Jianguo Wang,Xiaohua Lu

We report an approach of direct production of H 2 O 2 from water by applying altering potential in the electrocatalysis. By switching potentials periodically between positive to negative, oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) occurs sequentially on a single electrode loaded catalysts, which leads to the reduction of the newly-formed OER active species, forming H 2 O 2 directly. The H 2 O 2 production is dependent on the time and potentials of OER and ORR, which is optimized in this study. Besides, a waiting time is set after each period to let H 2 O 2 diffusion from the catalyst surface. Different catalysts are employed to test the feasibility of this approach, including glassy carbon, graphene oxide, nickel particles, nickel foam, and palladium particles. All these catalysts result in the production of H 2 O 2 at various reaction rates. Ni offers the highest H 2 O 2 productivity. With the prolonging of the reaction time, the decomposition of H 2 O 2 occurs on the surface of Ni catalysts, which is inhibited by the addition of Zn into the catalysts. The in-situ generated H 2 O 2 is used for partial oxidation of propylene by passing propylene into the porous electrode during the reaction, which lead to the formation of dimethyl ether and adipic acid. This study shows a new route of the direct synthesis and utilization of H 2 O 2 for the generation of valuable chemicals.

Narrow-Band Blue-Emitting Indium Phosphide Quantum Dots Induced by Highly Active Zn Precursor

Xiaopeng Zhou,Jiejun Ren,Wenlei Cao,Andries Meijerink,Yuhua Wang

Colloidal indium phosphide quantum dots (In(Zn)P/ZnS QDs) show potential for application in the field of light emitting diodes (LED) and Mini/Micro-LEDs displays due to their tunable emission and low toxicity. However, the performance of blue-emitting indium phosphide QDs is still lagging behind that of red and green. Herein, a facile method to overcome this difficulty is proposed. The highly active Zn(ClO 4 ) 2 precursor is injected into the reaction mixture during the nucleation process to enhance zinc incorporation, which generates the In(Zn)P alloy QDs with enlarged bandgap. At the same time, the increase of zinc content can inhibit excessive growth of In(Zn)P QDs, and significantly improve its size distribution. The monodisperse In(Zn)P/ZnS QDs exhibit excellent blue emission (466 nm) and have the narrowest full width at half maxima (41 nm) of blue emission In(Zn)P QDs ever reported. This work provides a feasible and effective strategy for obtaining narrow-band blue-emitting In(Zn)P/ZnS QDs.

Tb3+ and Bi3+ Co-Doping of Lead-Free Cs2NaInCl6 Double Perovskite Nanocrystals for Tailoring Optical Properties

Yang Yu,Wei Zhou,Cheng Li,Peigeng Han,Hui Li,Kun Zhao

Lead halide perovskites have achieved remarkable success in various photovoltaic and optoelectronic applications, especially solar cells and light-emitting diodes (LEDs). Despite the significant advances of lead halide perovskites, lead toxicity and insufficient stability limit their commercialization. Lead-free double perovskites (DPs) are potential materials to address these issues because of their non-toxicity and high stability. By doping DP nanocrystals (NCs) with lanthanide ions (Ln3+), it is possible to make them more stable and impart their optical properties. In this work, a variable temperature hot injection method is used to synthesize lead-free Tb3+-doped Cs2NaInCl6DP NCs, which exhibit a major narrow green photoluminescence (PL) peak at 544 nm derived from the transition of Tb3+ 5D4→7F5. With further Bi3+co-doping, the Tb3+-Bi3+-co-doped Cs2NaInCl6DP NCs are not only directly excited at 280 nm but are also excited at 310 nm and 342 nm. The latter have a higher PL intensity because partial Tb3+ions are excited through more efficient energy transfer channels from the Bi3+to the Tb3+ions. The investigation of the underlying mechanism between the intrinsic emission of Cs2NaInCl6NCs and the narrow green PL caused by lanthanide ion doping in this paper will facilitate the development of lead-free halide perovskite NCs.Keywords:lead-free double perovskite;lanthanide ion doping;Cs2NaInCl6;nanocrystals

A novel and sensitive ratiometric fluorescent quantum dot-based biosensor for alkaline phosphatase detection in biological samples via the inner-filter effect

Penghui Hu,Ruiyan Huang,Ye Xu,Tengfei Li,Jun Yin,Yu Yang,Yuan Liang,Xiaohan Mao,Li Ding,Chang Shu

Alkaline phosphatase (ALP) is an important biomarker whose abnormal level in activity is associated with hepatobiliary, skeletal, and renal diseases as well as cancer. Herein, we synthesized ZnSe@ZnS quantum dots (ZnSe@ZnS QDs) and Mn-doped ZnS quantum dots (Mn:ZnS QDs) as fluorophores to establish the ratiometric fluorescent assay for ALP activity detection in biological samples. p-Nitrophenyl phosphate (PNPP) was used as a substrate for ALP, and the overlaps between absorption spectra of PNPP and excitation spectra of QDs resulted in sharp fluorescence quenching. Under the catalysis of ALP, PNPP was hydrolyzed into p-nitrophenol (PNP), which caused a red shift of absorption band of PNPP and fluorescence recovery of Mn:ZnS QDs (585 nm). However, the overlaps between absorption spectra of PNP and emission spectra of ZnSe@ZnS QDs led a further quenching of ZnSe@ZnS QDs (405 nm). Therefore, the ratiometric fluorescent signals (F585/F405) were associated with activity of ALP based on bidirectional responses of QDs to the concentration of PNPP. Under the optimum conditions, the method exhibited a good linear relationship from 4 to 96 U per L (R2 = 0.9969) with the detection limit of 0.57 U per L. Moreover, the method was successfully applied for detecting the ALP activity in a complex biological matrix (human serum and HepG2 cells) with impressive specificity. In particular, the complicated chemical modifications of QDs and pretreatments of biological samples were not required in the whole detection procedures. Therefore, it not only provided a sensitive, specific and simple approach to clinical ALP activity detection, but it also provided support for early diagnosis of diseases.

A clinically translatable kit for MRI/NMI dual-modality nanoprobes based on anchoring group-mediated radiolabeling

Lei Chen,Yun Gao,Jianxian Ge,Yi Zhou,Zhe Yang,Cang Li,Baoxing Huang,Kuan Lu,Dandan Kou,Dandan Zhou,Can Chen,Sixia Wang,Shuwang Wu,Jianfeng Zeng,Gang Huang,Mingyuan Gao

Magnetic resonance imaging (MRI)/nuclear medicine imaging (NMI) dual-modality imaging based on radiolabeled nanoparticles has been increasingly exploited for accurate diagnosis of tumor and cardiovascular diseases by virtue of high spatial resolution and high sensitivity. However, significant challenges exist in pursuing truly clinical applications, including massive preparation and rapid radiolabeling of nanoparticles. Herein, we report a clinically translatable kit for the convenient construction of MRI/NMI nanoprobes relying on the flow-synthesis and anchoring group-mediated radiolabeling (LAGMERAL) of iron oxide nanoparticles. First, homogeneous iron oxide nanoparticles with excellent performance were successfully obtained on a large scale by flow synthesis, followed by the surface anchoring of diphosphonate-polyethylene glycol (DP-PEG) to simultaneously render the underlying nanoparticles biocompatible and competent in robust labeling of radioactive metal ions. Moreover, to enable convenient and safe usage in clinics, the DP-PEG modified nanoparticle solution was freeze-dried and sterilized to make a radiolabeling kit followed by careful evaluations of its in vitro and in vivo performance and applicability. The results showed that 99mTc labeled nanoprobes are effectively obtained with a labeling yield of over 95% in 30 minutes after simply injecting Na[99mTcO4] solution into the kit. In addition, the Fe3O4 nanoparticles sealed in the kit can well stand long-term storage even for 300 days without deteriorating the colloidal stability and radiolabeling yield. Upon intravenous injection of the as-prepared radiolabeled nanoprobes, high-resolution vascular images of mice were obtained by vascular SPECT imaging and magnetic resonance angiography, demonstrating the promising clinical translational value of our radiolabeling kit.

Nitrogen doping to accelerate the phase transition to ordered intermetallic Pt3Co catalyst for the oxygen reduction reaction in fuel cells

Weicheng Xu,Zhipeng Zhu,Yucheng Wang,Peixin Cui,Lei Tong,Kuangmin Zhao,Jiayin Yuan,Zhi-You Zhou,Hai-Wei Liang,Na Tian,Shi-Gang Sun

Ordered intermetallic Pt–M alloys are foreseen to be promising as next-generation low-Pt catalysts for the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs) due to their high catalytic activity and stability. Nevertheless, the disorder-to-order intermetallic phase transition often needs to proceed at elevated annealing temperature for a long time, which leads to severe particle agglomeration. Herein, an efficient nitrogen (N)-doping strategy is developed to speed up such phase transition in an intermetallic Pt3Co alloy catalyst, which shortens the annealing duration by 3–5 fold at a temperature of 600–800 °C. Such a strategy can not only minimize the particle agglomeration but also effectively optimize the electronic structure of surface Pt atoms with the incorporated N. The prepared N-doped ordered intermetallic Pt3Co catalyst exhibits high ORR activity among the best of the state-of-the-art, with mass activities of 1.21 and 1.20 A mgPt−1 at 0.90 V in rotating disk electrode (RDE) and proton exchange membrane fuel cell (PEMFC) tests, respectively. Moreover, with the total Pt loading of 0.15 mgPt cm−2, the H2–air PEMFC delivers a power density of 1.27 W cm−2 at 150 kPaabs and 0.6 V, corresponding to a high Pt utilization of 0.118 gPt kW−1 that has surpassed the DOE 2025 target (0.125 gPt kW−1). This study paves a new way to develop high-performance low-Pt ORR catalysts for PEMFCs.

High-performance electrochemiluminescence sensors based on ultra-stable perovskite quantum dots@ZIF-8 composites for aflatoxin B1 monitoring in corn samples

Qian Wang,Chengyi Xiong,Jingwen Li,Qianchun Deng,Xiuhua Zhang,Shengfu Wang,Miao-Miao Chen

Aflatoxin B1 (AFB1) that is prone to contaminate corns brings a serious threat to human health. Therefore, it is of great significance to construct novel detection methods for AFB1 tracing. Here, methylamine perovskite quantum dots (MP QDs) encapsulated by ZIF-8 metal–organic frameworks (MP QDs@ZIF-8) were prepared and then ultra-stable electrochemiluminescence (ECL) sensors were developed. By the confinement of cavities structure, multiple MP QDs were crystallized and embedded inside ZIF-8 to form MP QDs@ZIF-8, achieving stable and robust ECL responds in aqueous environment. Further combined with AFB1-imprinted polymer, the constructed ECL sensor showed good selectivity and ultra-sensitivity (the detection limit was 3.5 fg/mL, S/N = 3) with a wide linear range from 11.55 fg/mL to 20 ng/mL for AFB1 quantification. Satisfactory recoveries in corn samples indicated the reliable practicability of the proposed sensor for AFB1 assay. This work provided a novel pathway in designing high-performance ECL sensing platform for food safety.