查找使用阿拉丁产品的科研文献

Highly Efficient Ir(III)-Coumarin Photo-Redox Catalyst for Synergetic Multi-Mode Cancer Photo-Therapy

Zhongxian Fan,Jiaen Xie,Tumpa Sadhukhan,Chao Liang,Can Huang,Wenqing Li,Tingxuan Li,Pingyu Zhang,Samya Banerjee,Krishnan Raghavachari,Huaiyi Huang

Graphical Four novel Ir(III) photo-catalysts ( Ir1 – Ir4 ) were synthesized and applied for photocatalytic cancer therapy. Upon blue and green light irradiation, these photocatalysts generated singlet oxygen and induced rapid photo-catalytic oxidation of the cellular coenzymes NAD(P)H. Ir2 triggered promising photo-induced anticancer activity via induction of intracellular redox imbalance and exhibited ideal in vivo photo-induced catalytic anticancer activity. Four photo-catalysts of the general formula [Ir(CO6/ppy) 2 (L)]Cl where CO6=coumarin 6 ( Ir1 – Ir3 ), ppy=2-phenylpyridine ( Ir4 ), L=4′-(3,5-di-tert-butylphenyl)-2,2′ : 6′,2′′-terpyridine ( Ir1 ), 4′-(3,5-bis(trifluoromethyl)phenyl)-2,2′ : 6′,2′′-terpyridine ( Ir2 and Ir4 ), and 4-([2,2′ : 6′,2′′-terpyridin]-4′-yl)-N,N-dimethylaniline ( Ir3 ) were synthesized and characterized. These photostable photo-catalysts ( Ir1 – Ir3 ) showed strong visible light absorption between 400–550 nm. Upon light irradiation (465 and 525 nm), Ir1 – Ir3 generated singlet oxygen and induced rapidly photo-catalytic oxidation of cellular coenzymes NAD(P)H. Ir1 – Ir3 showed time-dependent cellular uptake with excellent intracellular retention efficiency. Upon green light irradiation (525 nm), Ir2 provided a much higher photo-index (PI=793) than the clinically used photosensitizer, 5-aminolevulinicacid (5-ALA, PI>30) against HeLa cancer cells. The observed necro-apoptotic anticancer activity of Ir2 was due to the Ir2 triggered photo-induced intracellular redox imbalance (by NAD(P)H oxidation and ROS generation) and change in the mitochondrial membrane potential. Remarkably, Ir2 showed in vivo photo-induced catalytic anticancer activity in mouse models.

Highly Efficient Ir–CoOx Hybrid Nanostructures for the Selective Hydrogenation of Furfural to Furfuryl Alcohol

Hongbo Yu,Jihao Zhao,Chunzheng Wu,Bo Yan,Shuangliang Zhao,Hongfeng Yin,Shenghu Zhou

Decoration of noble metals with transition-metal oxides has been intensively studied for heterogeneous catalysis. However, controllable syntheses of metal–metal oxide heterostructures are difficult, and elucidation of such interfaces is still challenging. In this work, supported IrCo alloy nanoparticles are transformed into supported Ir–CoOx close-contact nanostructures by in situ calcination and following selective reduction. Relative to Ir/Al2O3, Ir–CoOx/Al2O3 shows greatly enhanced activities for the hydrogenation of furfural derivatives to the corresponding furfuryl alcohol derivatives with more than 99% selectivity and demonstrates significantly improved activities and selectivity for hydrogenations of α,β-unsaturated aldehydes to α,β-unsaturated alcohols. The modification of Ir surfaces with CoOx prevents Ir nanoparticles from growing, achieving high thermal and catalytic stabilities. Theoretic calculation suggests that the better catalytic performance of Ir–CoOx/Al2O3 is ascribed to the Ir–CoOx interaction, which promotes the absorption of furfural as well as desorption of furfuryl alcohol, resulting in enhanced catalytic activities.

Stable and high-performance Ir electrocatalyst with boosted utilization efficiency in acidic overall water splitting

Yuhua Xie,Xinxin Yu,Xianwei Li,Xue Long,Chaofeng Chang,Zehui Yang

The industrialization of solid polymer electrolyte water electrolysis (SPEWE) dominantly relies on electrocatalyst with high stability and efficiency for oxygen evolution reaction (OER) catalysis. In this work, we report a facile method to construct α-Ni(OH) 2 @Ir core–shell nanoparticles as bifunctional electrocatalyst for acidic overall water splitting application. α-Ni(OH) 2 @Ir requires lower overpotentials (238 mV and 20 mV) to achieve 10 mA cm −2 in acidic OER and HER catalysis compared to benchmarked IrO 2 (332 mV) and Pt/C (36 mV); meanwhile, the OER mass activity at 1.55 V vs. RHE was 92 fold higher than IrO 2 ; HER mass activity at overpotential of 80 mV was 5 fold better than Pt/C. The boosted catalytic activity is due to the enhanced utilization efficiency of Ir stemmed from the ultrathin Ir shell (~1 nm). Moreover, 1.49 V is demanded for α-Ni(OH) 2 @Ir to attain 10 mA cm −2 in acidic overall water splitting, 110 mV lower than benchmarked Pt/C-IrO 2 system. Meanwhile, stable catalytic performance is recorded for 20 h.

Near-infrared emissive polymer-coated IR-820 nanoparticles assisted photothermal therapy for cervical cancer cells

Lijun Zhu,Jianjun Chen,Ting Yan,Gulinigaer Alimu,Xueliang Zhang,Shuang Chen,Mutalifu Aimaiti,Rong Ma,Nuernisha Alifu

Photothermal therapy (PTT) has attracted wide attention due to its noninvasiveness and its thermal ablation ability. As photothermal agents are crucial factor in PTT, those with the characteristics of biocompatibility, non-toxicity and high photothermal stability have attracted great interest. In this work, new indocyanine green (IR-820) was utilized as a photothermal agent and near-infrared (NIR) fluorescence imaging nanoprobe. To improve the biocompatibility, poly(styrene-co-maleic anhydride) (PSMA) was utilized to encapsulate the IR-820 molecules to form novel IR-820@PSMA nanoparticles (NPs). Then, the optical and thermal properties of IR-820@PSMA NPs were studied in detail. The IR-820@PSMA NPs showed excellent photothermal stability and biocompatibility. The cellular uptaking ability of the IR-820@PSMA NPs was further confirmed in HeLa cells by the NIR fluorescent confocal microscopic imaging technique. The IR-820@PSMA NPs assisted PTT of living HeLa cells was conducted under 793 nm laser excitation, and a high PTT efficiency of 73.3% was obtained.

Interlayer confinement synthesis of Ir nanodots/dual carbon as an electrocatalyst for overall water splitting

Yaru Li,Yu-Quan Zhu,Weili Xin,Song Hong,Xiaoying Zhao,Hong Yan,Sailong Xu

Rationally designing low-content and high-efficiency noble metal nanodots offers opportunities for enhancing their electrocatalytic performance for water splitting. However, the preparation of highly dispersed nanodot electrocatalysts remains a challenge. Herein, we report the interlayer confinement synthesis of sulfur-doped carbon-coated Ir nanodots on reduced graphene oxide (Ir@S–C/rGO) as an electrocatalyst for overall water splitting. The Ir@S–C/rGO composite is derived from a guest/host precursor of dodecyl sulfate (DS−)/hexachloroiridate (IrCl63−) co-intercalated MgAl-layered double hydroxide on a GO support. The composite has these advantages: Ir nanodots (1.7 ± 0.2 nm) with a low Ir amount of 6.2 wt%, S-doped carbonaceous encapsulation and a rGO support, as well as a large specific surface area of 194 m2 g−1 and meso-/macropore size distribution. The composite electrode requires overpotentials of 280 and 300 mV at 10 and 20 mA cm−2, respectively, for the oxygen evolution reaction (OER) in alkaline conditions; and 20 and 35 mV at 10 and 20 mA cm−2 for the hydrogen evolution reaction (HER) in alkaline conditions, respectively. Furthermore, a two-electrode electrolyzer yields a current density of 10 mA cm−2 at 1.51 V for overall water splitting. Moreover, the density functional theory calculations show that the charge distribution of the Ir nanoclusters facilitates the enhancement of the electrocatalytic activity for the OER, and the sulfur-doped carbon lowers the work function of the Ir particles on graphene; both of which underpin the enhancement. Our guest/host-assisted interlayer nanoconfinement can promise an effective synthesis strategy for designing and preparing well-dispersed nanodots as promising electrocatalysts for water splitting.

Construction of a highly stable natural silicate-supported molybdenum catalyst for efficient epoxidation of olefins

Xingrui Yu,Chao Xiong,Yichao Liang,Xiantai Zhou,Can Xue

Epoxides are important bulk chemicals, playing irreplaceable role in the chemical industry, but facing serious pollution and low productivity in the production process. Therefore, the development of green and efficient epoxidation of olefins by stable catalysts with low prices is of great significance. In this study, a Mo-MATP catalyst was prepared by modifying Mo(CO)₆ on attapulgite through Si-O bonding. Mo-MATP exhibits excellent performance (99% yield of cyclooctane oxide, CYCO) and stability (80% selectivity of CYCO after 17 cycles), highly tert -butyl hydroperoxide (TBHP) utilization, and extensive substrate scalability. Furthermore, the in-situ Fourier Transform Infrared Spectroscopy (FT-IR), Electron Spin-resonance Spectroscopy (ESR) and High Resolution Mass Spectrometry (HRMS) spectra suggest that TBHP would be activated by Mo-MATP to generate peroxyl radicals, which then oxidize alkenes to their corresponding epoxides. In this study, the stable loading of Mo would largely solve the problem of Mo loss during the catalytic process, thus providing a stable and dispersed Mo active center, enabling the catalyst to possess high catalytic performance and recycling stability.

Insight into decomposition of formic acid to syngas required for Rh-catalyzed hydroformylation of olefins

Lei Liu,Xiao-Chao Chen,Shu-Qing Yang,Yin-Qing Yao,Yong Lu,Ye Liu

Formic acid (FA) is one kind of important bulk chemicals, which is recognized as a sustainable and eco-friendly energy carrier to transport H 2 via dehydrogenation or CO via decarbonylation. Expectantly, FA upon decomposition into H 2 and CO could be used as the syngas alternative for hydroformylation. In this paper, the behaviors of FA to release H 2 as well as CO following the distinct pathways were carefully investigated for the first time, and then established a new hydroformylation protocol free of syngas. It was found that the atmospheric hydroformylation of olefins with formic acid (FA) as syngas alternative was smoothly fulfilled over Xantphos ( L1 ) modified Rh-catalyst under mild conditions (80 °C, Rh concentration 1 mol %, 14 h), resulting in >90% conversion of the olefins along with the high selectivity to the target aldehydes (>93%). By using FA as syngas source, the side-reaction of olefin-hydrogenation was greatly depressed. The in situ FT-IR and the high-pressure 1 H NMR spectroscopic analyses were applied to reveal how FA behaves dually as CO surrogate and hydrogen source over L1 -Rh(acac)(CO) 2 catalytic system, based on which the deeply insight into the catalytic mechanism of hydroformylation of olefins with FA as syngas alternative was offered.

Crystallization behavior of boron in low-temperature immobilization of iodine waste

Yaxin Feng,Guilin Wei,Yi Liu,Wenhong Han,Yan Chen,Runjie Sun,Lin Peng,Meihua Ma,Yu Zhang,Zhentao Zhang,Xirui Lu

The immobilization of iodine waste is a challenge in the field of nuclear waste . In this work, iodine waste (silver-coated silica gel with different iodine loadings) was immobilized at low-sintering temperatures (500, 550, and 600 ​°C). XRD represented that the crystallized phases of the sintered matrix consist of AgI and B 2 O 3 . The crystallization behavior of boron can be found as the sintering temperature increased from 500 ​°C to 600 ​°C. FT-IR results proved that in the process of crystallization, part of the microstructure related to B–O stretching transformed from [BO 4 ] to [BO 3 ] units, which benefits low-temperature iodine waste immobilization due to the bonding energy of [BO 3 ] is higher than that of [BO 4 ]. Our work reveals the B-related microstructure transition in low-temperature immobilization iodine waste.

Asymmetric photooxidation of glycerol to hydroxypyruvic acid over Rb–Ir catalytic pairs on poly(heptazine imides)

Teng Zhenyuan,Zhang Zhenzong,Tu Ying,Zhang Qitao,Jian Nan,Yang Liujun,Xiao Jiadong,Ding Jie,Huang Longzhen,Teruhsia Ohno,Wang Chengyin,Zhang Dengsong,Yu Han,Lu Jianmei,Su Chenliang,Liu Bin

Selective asymmetric oxidation of glycerol (GLY) to hydroxypyruvic acid (HPA) offers an attractive approach for chiral drug synthesis, but this process is highly challenging. Here we develop a photocatalytic method to achieve heterogeneous selective photooxidation of GLY to HPA over rubidium (Rb) and iridium (Ir) catalytic pairs decorated on a poly(heptazine imide) framework. The Rb sites effectively adsorb GLY molecules through the terminal –OH groups, thus inhibiting their oxidation during photoreaction, while the Ir sites enhance the oxygen reduction reaction and the in situ generated surficial oxygen-reduction radicals on Ir can protect the reactive C-centred radical intermediates produced during photooxidation. The spatial arrangement of Rb and Ir sites facilitates hydrogen extraction—an essential rate-determining step for GLY photooxidation—and protects C3 radical intermediates from overoxidation. This photocatalytic system achieves a remarkable productivity for HPA synthesis (~8,000 μmol of HPA per gram of photocatalyst per hour) under visible-light illumination.

All-solution-processed UV-IR broadband trilayer photodetectors with CsPbBr3 colloidal nanocrystals as carriers-extracting layer

Muhammad Imran Saleem,Shengyi Yang,Muhammad Sulaman,Jinming Hu,Perumal Veeramalai Chandrasekar,Yuansheng Shi,Ruonan Zhi,Attia Batool,Bingsuo Zou

Colloidal quantum dots (CQDs) are very promising nanomaterials for optoelectronics due to their tunable bandgap and quantum confinement effect. All-inorganic CsPbX3 (X = Br, Cl and I) perovskite nanocrystals (NCs) have attracted enormous interests owing to their promising and exciting applications in photovoltaic devices. In this paper, all-solution-processed UV-IR broadband trilayer photodetectors ITO/ZnO/PbS/CsPbBr3/Au and ITO/ZnO/CsPbBr3/PbS/Au with high performance were presented. The role of CsPbBr3 QDs layer as the carriers-extracting layer in the trilayer devices was discussed. As compared with bilayer device ITO/ZnO/PbS/Au, both the dark currents and photocurrents under illumination from trilayer photodetectors are enhanced, but the trilayer photodetector ITO/ZnO(80 nm)/PbS(150 nm)/CsPbBr3(50 nm)/Au showed a maximum specific detectivity (D*) of 8.3 × 1012 Jones with a responsivity (R) of 35 A W−1 under 1.6 mW cm−2 980 nm illumination. However, another trilayer photodetector ITO/ZnO(80 nm)/CsPbBr3(50 nm)/PbS(150 nm)/Au showed a maximum D* of 1.73 × 1012 Jones with a R of 5.31 A W−1 under 6.8 mW cm−2 405 nm illumination. Further, the underlying mechanism for the enhanced performance of trilayer photodetectors was discussed. Thus, this strategy of all-solution-processed heterojunction configuration paves a facile way for broadband photodetectors with high performance.

A Preliminary Study on a New Epoxy Resin IR-3 for High-Field Superconducting Magnet Applications

Huanli Yao,Yalin Zhao,Hua Zhang,Yingzhe Wang,Chengtao Wang,Zhen Zhang,Ze Feng,Jinrui Shi,Xin Chen,Jin Zhou,Chunyan Li,Juan Wang,Feipeng Ning,Rongjin Huang,Qingjin Xu

Ir doping improved oxygen activation of WO3 for boosting acetone sensing performance at low working temperature

Jian Ding,Zhen Li,Yongchao Wang,Yi Liu,Fei Li,Xinru Yu,Peiqi Huang,Yang Wang

Thermally excited oxygen activation is the key to realize gas sensing by semiconductor. However, the relevant strategies and mechanisms are rarely studied. Herewith, the model material of highly oxygen catalytic active Ir doped WO 3 (Ir-WO 3 ) is prepared to elucidate the impact of enhanced oxygen activation on sensing performance. Interestingly, the 0.5 wt% Ir doped WO 3 successfully reduced the working temperature of WO 3 from 370 to 260 ℃ and significantly enhanced the response from 25.1 to 127.9 (at 50 ppm) for acetone. Meanwhile, the sensor also has fast response/recovery times (∼8.3/3.8 s), long-term stability, low detection limit (19 ppb) and high selectivity. Gas sensitive performance tests, in situ -DRIFTS and DFT calculations reveal that the Ir doping facilitates the oxygen adsorption and activation, which can significantly weaken the activation energy of acetone at low temperatures and contribute to enhance sensing performance. Our work paves a new pathway to improving metal oxide-based gas sensors at lower operating temperatures.