查找使用阿拉丁产品的科研文献

Modulating Water Splitting Kinetics via Charge Transfer and Interfacial Hydrogen Spillover Effect for Robust Hydrogen Evolution Catalysis in Alkaline Media

Yiming Jiang,Juncai Leng,Shiqi Zhang,Tingyi Zhou,Mingxuan Liu,Shuoming Liu,Yahui Gao,Jianwei Zhao,Lei Yang,Li Li,Wei Zhao

Designing and synthesizing advanced electrocatalysts with superior intrinsic activity toward hydrogen evolution reaction (HER) in alkaline media is critical for the hydrogen economy. Herein, a novel Ir@Rhene heterojunction electrocatalyst is synthesized via epitaxially confining ultrasmall and low-coordinate Ir nanoclusters on the ultrathin Rh metallene accompanying the formation of Ir/IrO 2 Janus nanoparticles. The as-prepared heterojunctions display outstanding alkaline HER activity, with an overpotential of only 17 mV at 10 mA cm −2 and an ultralow Tafel slope of 14.7 mV dec −1 . Both structural characterizations and theoretical calculations demonstrate that the Ir@Rhene heterointerfaces induce charge density redistribution, resulting in the increment of the electron density around the O atoms in the IrO 2 site and thus delivering much lower water dissociation energy. In addition, the dual-site synergetic effects between IrO 2 and Ir/Rh interface trigger and improve the interfacial hydrogen spillover, thereby subtly avoiding the steric blocking of the active site and eventually accelerating the alkaline HER kinetics.

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.

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.

Developing long-lifetime luminescent Ir(III) complexes for facile detection of pesticide residue in complex matrices

Menghan Liu,Xiuqi Fan,Zhe Li,Guangyu Li,Tiangang Zhu,Ruyu Zhang,Lihua Lu

To develop long-lifetime luminescent Iridium(III) [Ir(III)] complexes, two novel series ( a1 – a4 and b1 – b4) were designed and synthesized, and their structure-photophysical property relationships were systematically investigated. Notably, introducing a sulfur (S) atom simultaneously extends the luminescence lifetime and enhances the quantum yield of these complexes. Among them, b3 stands out as an exceptional time-resolved emission spectroscopy (TRES) probe due to its prolonged lifetime and high quenching efficiency by polydopamine (PDA). By leveraging dual mechanisms, PDA-mediated quenching of b3 and thiocholine (TCh)-inhibited dopamine (DA) polymerization, a sensitive luminescent platform for malathion (MAL) detection was developed. The resulting detection platform achieves an ultra-low limit of detection (LOD) 0.32 nM within a linear range of 0.001–15.0 μM. Notably, the long-lived b3 (τ = 1.665 μs) permits effective MAL detection even in a highly fluorescent RhB matrix using TRES (LOD = 13.2 nM), whereas steady-state emission spectra (SSES)-based detections fail under such conditions. The successful application of b3 in real-sample analysis demonstrates the great potential of Ir(III) complexes in TRES-based detection. This work not only expands the repertoire of TRES probes but also presents a highly effective luminescent platform for pesticide detection.

Fe2+: MgF2 laser ceramics via Co-precipitation with 90% Mid-IR transparency and enhanced thermal conductivity

Xindan Li,Ming Yin,Xincheng Cai,Zhuoying Jia,Hongjiang He,Mingjing Tang,Xiaoqiang Li,Shengquan Yu

Polycrystalline MgF 2 is an attractive mid-infrared laser host material, yet its widespread application in high-power systems is limited by its inferior thermal conductivity compared to single-crystal materials, resulting in inefficient heat dissipation. To address this challenge, we successfully designed and synthesized Fe 2+ : MgF 2 transparent ceramics using a strategic wet chemical coprecipitation method combined with hot-press sintering. This method enables precise Fe 2+ doping within the MgF 2 lattice (Fe x Mg 1-x F 2 , 0.0002≤x ≤ 0.05), with doping effects clearly confirmed by XRD, XPS, and TEM analyses. The resulting ceramics exhibit outstanding mid-infrared transmission properties, with 1-mm-thick samples achieving 90% linear transmittance at 5.7 μm wavelength. More importantly, Fe 2+ incorporation significantly enhances thermal conductivity—peaking at 20.3 W/(m·K), a substantial increase over the baseline value of 11.6 W/(m·K)—while simultaneously raising Vickers hardness to 5.49 ± 0.54 GPa, fulfilling the core design objective. This simultaneous achievement of high optical quality and exceptional thermal management demonstrates that Fe 2+ : MgF 2 transparent ceramics represent a highly promising and reliable candidate material for high-power mid-infrared laser applications.

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

Visible light-harvesting cyclometalated Ir(III) complexes as triplet photosensitizers for triplet–triplet annihilation based upconversion

Lihua Ma,Huimin Guo,Qiuting Li,Song Guo,Jianzhang Zhao

Visible light-harvesting cyclometalated Ir(III) complexes with 3-(2-benzothiazoly)-7-diethylaminocoumarin as the C^N cyclometalation ligands were prepared. The ancillary N^N ligand is either 6-piperidine naphthalimide-phenanthroline (Ir-1) or 9-aminophenanthroline (Ir-3). Ir(ppy)2(Phen) was prepared as model complex (Ir-2). Ir-1 and Ir-3 show strong absorption of visible light (ε = 109 000 M−1 cm−1 or 112 000 M−1 cm−1 at 486 or 484 nm, respectively). All the complexes show room temperature phosphorescence with drastically different phosphorescence quantum yields (ΦP = 4.3%, 44.3% and 46.0% for Ir-1, Ir-2 and Ir-3, respectively). With steady state and time-resolved spectra, as well as DFT calculations, the T1 excited states of Ir-1 and Ir-3 were proposed to be the 3IL state, whereas the 3MLCT state was proposed for Ir-2. Long-lived emissive triplet excited states (7.6 μs and 54.5 μs) were observed for Ir-1 and Ir-3, compared to the short T1 excited state lifetime of Ir-2 (1.2 μs). The complexes were used as triplet photosensitizers for triplet–triplet annihilation upconversion and upconversion quantum yields (ΦUC) of 19.3% and 12.7% were observed for Ir-1 and Ir-3, respectively. No upconversion was observed for Ir-2 under the same experimental conditions.

WO3 Nanosheet-Supported IrW Alloy for High-Performance Acidic Overall Water Splitting with Low Ir Loading

Dinghua Zhou,Min He,Yunxuan Ding,Jiaguo Yu,Ke Fan,Licheng Sun

Precious metals (like Ir, Ru, and Pt) and their derivatives are the benchmark catalysts for water splitting in acidic media due to their high stability and activity. However, the high cost and scarcity of these materials hamper the large-scale applications. To solve this issue, construction of catalysts containing low content of precious metals with high intrinsic activity can be an efficient strategy, which expectedly can decrease the cost but meanwhile preserve the activity. Herein, we synthesized an IrW/WO3 array catalyst by in situ formation of IrW alloy on hierarchical WO3 nanosheet arrays. With extremely low Ir content of 1.25 wt % in 0.5 M H2SO4, this composite catalyst not only shows superior water oxidation activity (the overpotential at 10 mA cm–2 is only 229 mV, significantly lower than that of the commercial IrO2 (358 mV)) but also exhibits excellent proton reduction performance (the overpotential at −10 mA cm–2 is 49 mV, close to that of commercial Pt/C catalyst (42 mV)), showing promising bifunctionality for the overall water splitting. As a result, only 1.5 V is needed to drive the overall water splitting at 10 mA cm–2 with a good long-term stability under acidic conditions. These remarkable features can be ascribed to the abundant active sites exposed by the three-dimensional nanostructure, and the high intrinsic activity per Ir site. The theoretical calculation verifies that Ir sites in IrW surface after oxidation have a higher intrinsic activity than IrO2 for water oxidation. We believe this research can supply a strategy to design highly active and stable catalysts with low loading of noble metals for acidic water splitting.

Ir-doped NiV LDH realizing high-efficient and stable overall water and urea assisted water splitting

Qiudi Mao,Zhishan Li,Hua Wang,Kongzhai Li,Chao Liu

Advances in hydrogen energy technology require the urgent development of electrocatalysts suitable for urea-assisted and overall water splitting. This study successfully synthesized a trifunctional electrocatalyst featuring an iridium-doped NiV LDH structure via a simple hydrothermal method. NiVIr LDH-4 shows remarkable trifunctional catalytic activity. It operates stably for over 100   h at a current density of 100   mA   cm −2 in HER, OER, and UOR processes, as well as in overall water splitting and urea-assisted water splitting systems. These results provide a promising strategy for the development of advanced electrocatalysts that enable energy‑efficient hydrogen production alongside simultaneous remediation of urea‑laden wastewater.

Study on IrOx-coated gradient-distributed IrOx/Ir with low crystallinity for acidic oxygen evolution reaction

Yuanyi xiang,Haiwen Qiu,Yuqing Huang,Qinghong Huang,Xiaoyan Luo,Zhou Yi,Yuping Wu

Proton exchange membrane (PEM) water electrolysis has broad application prospects for clean hydrogen production owing to its high efficiency, compact structure, rapid response, and flexible load regulation. However, the sluggish kinetics of the oxygen evolution reaction (OER) under strongly acidic conditions still poses a major challenge to the development of efficient and stable acidic OER electrocatalysts. In this work, a low-crystallinity IrO x /Ir catalyst with a gradient-distributed IrO x coating was successfully prepared by a hydrothermal method. In acidic OER tests, the catalyst exhibited excellent electrocatalytic performance, delivering a mass activity 218 times higher than that of commercial IrO 2 at 1.55 V vs. RHE, and requiring an overpotential of only 231 mV to reach 10 mA·cm −2 . The incorporation of non-crystalline metallic Ir 0 significantly improves the electrical conductivity and intrinsic catalytic activity of the catalyst. Meanwhile, the outer layer of more crystalline iridium oxide effectively protects the highly active low-crystallinity iridium oxide in the interior from dissolution and corrosion, so that the catalyst shows no obvious activity decay after 300 h of continuous operation, indicating good stability.

Regulating the formation type by Ir of intermediates to suppress product overoxidation in photocatalytic methane conversion

Yuhang Zhang,Yi Li,Yuehan Cao,Yingjie Shuai,Yu Zhou,Ying Zhou

Methane, as an abundant resource, serves not only as an excellent fossil fuel but also as a pivotal feedstock for synthesizing high-value-added chemical products. Solar-driven methane conversion offers a highly promising pathway for the direct production of high-value chemicals such as methanol (CH 3 OH) and formaldehyde (HCHO) under mild conditions. However, the core challenge of this conversion process lies in the tendency of target products to undergo over-oxidation, resulting in low selectivity—a critical bottleneck that urgently requires breakthrough in this field. Herein, we constructed an Ir-modified CdS (Ir x /CdS) photocatalytic system and proposed that regulating the generation types of key reaction intermediates via metallic Ir is an effective strategy to enhance the selectivity of target products and suppress over-oxidation. In situ diffuse reflectance infrared Fourier transform spectroscopy ( in situ DRIFTS) confirmed that the types of key intermediates generated during methane activation differ, which decisively influences the product distribution. On pure CdS surfaces, the key intermediate *CH 3 O tends to participate in subsequent deep oxidation reactions via its O atom, ultimately leading to over-oxidized products like CO 2 . In contrast, after Ir loading, the key reaction intermediate shifts to *CH 3 . The Ir sites facilitate the conversion of *CH 3 to ‧CH 3 radicals through localized electron transfer, and the generated ‧CH 3 radicals rapidly combine with ‧OH radicals to selectively form CH 3 OH. The performance evaluation of photocatalytic methane conversion demonstrated that under conditions of 60 °C, 0.1 MPa, and molecular oxygen as the oxidant, the 0.50 wt% Ir-loaded Ir 0.50 /CdS sample exhibited optimal performance: the yield of oxygenated liquid products (CH 3 OH and HCHO) reached 509.2 μmol g −1 h −1 , with overall selectivity enhanced to 88 %. Characterization techniques such as X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM) revealed the coexistence of two valence states of Ir on the catalyst surface (metallic Ir 0 and oxidized Ir 4+ ), with the metallic state being dominant. The strategy proposed in this work—regulating intermediate species generation via metal modification to inhibit over-oxidation—provides a novel approach for the efficient conversion of methane into high-value oxygenated chemicals.