CHEMISTRY OF MATERIALS
·
2019
·
IF 10.159
Tongtong Yu,Shanpeng Wang,Xiang Zhang,Chenning Li,Jie Qiao,Ning Jia,Bing Han,Sheng-Qing Xia,Xutang Tao
Mid-infrared (MIR) nonlinear optical (NLO) crystals are crucial in generating MIR lasers, which are important in civilian and military applications. Compared to the extensively investigated ternary and quaternary chalcogenide NLO crystals, ternary phosphide crystals have a large nonlinearity coefficient and a wide transparency range. For instance, the well-known ternary chalcopyrite phosphide NLO crystal, ZnGeP2, possesses a large nonlinearity coefficient (deff = 75 pm/V) and a broad transmittance range of 0.75–12 μm. However, its applications in the far-infrared laser range were hindered by its strong absorption near 9 and 10–12 μm. Here, considering that Mn2+ not only makes contributions to large second-harmonic generation (SHG) response but also extends the transparency wavelength range, a new ternary chalcopyrite phosphide crystal, MnSiP2 (MSP), was rationally designed by substituting a II-site metal (Zn or Cd) for Mn in the II-Si-P2 family. In this work, the synthesis and single-crystal growth of MSP were systematically investigated. The theoretical and experimental characterizations demonstrated that MSP exhibits a good balance between strong SHG behavior (6 × AgGaS2) and large laser damage threshold (about 70 MW/cm2). Specifically, the long-wavelength MIR cutoff edge of MSP is 18.2 μm, and the outstanding terahertz (THz) transmittance covers the range of 0.4–2.0 THz, indicating the ultrabroad transparency range. This work may provide a feasible strategy and impel one to search for promising outstanding MIR NLO crystals in the ternary phosphide family.
研究领域:
材料科学
·
光学
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产品关联
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2019
·Vol. 103
·期 4
·2663-2673
·
IF 3.094
Boo-Hyun Choi,Dae-Su Kim,Ku-Tak Lee,Bum-Joo Kim,Jeong-Su Kang,Sahn Nahm
Hydrothermally synthesized ZnS nanopowders comprising small and large particles were used to synthesize ZnS ceramics. Small particles (200 nm) existed in the gaps between the large particles (0.7 μm) and assisted the densification of the ZnS ceramics. ZnS ceramics sintered at low temperatures (<1000°C) exhibited small grains with large grain-boundary areas that provided diffusion paths for carbon ions from the graphite mold, resulting in carbonate absorption bands. ZnS ceramics sintered at high temperatures (≥1000°C) for a long time (≥2.0 hours) exhibited a dense microstructure with very large grains (>500 μm). The ZnS liquid phase, which was formed at approximately 980°C, assisted the densification and grain growth of the ZnS ceramics. A 3.0-mm-thick ZnS ceramic sintered at 1000°C for 16 hours showed a high Knoop hardness (321 kgf/mm 2 ) and a high transmittance of 71% in the wavelength range 6.0-12 μm without carbonate absorption bands.
研究领域:
材料科学
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光学工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
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.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
CATALYSIS TODAY
·
2018
·
IF 4.667
Xiao Dong,Peng Zheng,Ai-Guo Zheng,Hui-Feng Li,Guo-Fu Xia,Ming-Feng Li,Ren-Yang Zheng,Bo-Qing Xu
Pt-Co/SiO 2 and Pt-Ir-Co/SiO 2 catalysts were prepared via galvanic replacement (GR) and employed for the hydrogenolytic ring-opening of methylcyclopentane (MCP). Selective deposition of the noble metals at the less expensive Co nanoparticle (NP) surface by GR greatly enhanced the utilization efficiency of the more active Pt or Pt and Ir atoms for the selective catalysis to the ring-opening reaction of MCP, as justified by comparison with catalysts from conventional impregnation preparation. The chemistry of GR was quantitatively studied by comprehension of the composition changes both in the preparation solution and in the solid samples. The structural features of GR catalysts were characterized as highly dispersed Pt or Pt and Ir clusters selectively deposited on Co NP surface. Compared to their counterparts from impregnation preparation, the GR catalysts showed much higher mass-specific activity normalized by overall noble metal loading (MSA NM ), due to the significantly enhanced utilization efficiency of Pt or Pt and Ir. In addition, the trimetallic Pt-Ir-Co/SiO 2 catalyst showed a distinctly higher MSA NM than the bimetallic Pt-Co/SiO 2 and Ir-Co/SiO 2 ones. This observation features a synergy between the highly dispersed Pt and Ir clusters in the catalysis, besides the enhanced noble metal utilization efficiency. Our catalytic data seem to suggest that a dicarbene mechanism was prevailing over the GR catalysts for the ring-opening reaction of MCP.
研究领域:
催化化学
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材料科学
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产品关联
DOI
高影响因子
NANOTECHNOLOGY
·
2018
·Vol. 29
·期 40
·405705
·
IF 3.404
Junnan Li,Ziwei Pan,Kebin Zhou
Developing efficient catalysts to accelerate the rate of oxygen evolution reaction (OER) is critical for photocatalytic water-splitting. In this work, metallic Ir, IrOx(OH)y, and core–shell Ir@IrOx(OH)y were synthesized and employed as OER catalysts for photocatalytic water oxidation. It was found that the Ir@IrOx(OH)y core–shell heterostructure catalyst showed the best photocatalytic performance among these three catalysts, with the oxygen evolution rate as high as 59.63 mmol g−1 h−1. Detailed investigations revealed that the excellent photocatalytic activity of Ir@IrOx(OH)y could be attributed to both the outstanding intrinsic activity of IrOx(OH)y shell and the efficient electron transfer between the photosensitizer and catalyst.
研究领域:
材料科学
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能源化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF POLYMER ANALYSIS AND CHARACTERIZATION
·
2013
·
IF 1.233
Shun
Ping Wang,Xiao
Deng Yang,Qing
Quan Bai,Tian
Duo Li
A comparative kinetic study of the urethane reactions of phenyl isocyanate and 1,2-, 1,3-, and 1,4-butanediol was carried out in dichloromethane solution with zirconium (IV) acetylacetonate as catalyst. In situ FT-IR was used to follow the kinetics of the reactions at a constant temperature of 15°–30°C. The rate constants for the reaction of the primary hydroxyl group and the secondary hydroxyl group were calculated as k
prim and k
sec, respectively. Analysis of the second-order rate constants of these systems indicated that k
prim follows 1,2-butanediol >1,3-butanediol >1,4-butanediol. The ratio of k
prim/k
sec in 1,2-butanediol was the highest and the order followed was the same as with the reaction rate. Activation energies and Eyring parameters were also determined for the urethane reaction of butanediols.
研究领域:
化学
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材料科学
✓ 已验证
DOI
高影响因子
ChemistrySelect
·
2022
·Vol. 7
·期 31
·e202201268
·
IF 2.307
Aixiao Fu,Mengqing Sun,Shifeng Jiang,Huanfei Xu,Guoqiang Xu
Graphical Pyrroles are important nitrogen-containing compound. Here, we constructed N, P-doped activated carbon supported Ir to perform the synthesis of pyrroles from alcohols and amino alcohols. The unique performance is attributed to the interaction between Ir and N, P-doped activated carbon. Pyrroles are a significant class of nitrogen-containing heterocyclic compounds and the derivatives. Here, an efficient procedure has been proposed for the loading of Ir on N, P-doped activated carbon to exploit pyrroles are synthesized from alcohols and amino alcohols. And the optimal conversion of 1-phenylethanol is up to 65 % with 2-phenylpyrrole selectivity of 80 %. The good performance is attributed to the interaction between metal Ir and N, P-doped activated carbon, which could also be confirmed from BET and XPS characterizations. What's more, the catalyst could be generally used for a range of reactions to produce pyrroles from alcohols and amino alcohols.
研究领域:
有机化学
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催化材料科学
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产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Jiabin Ji,Congyun Zhang,Xianfeng Yang,Fanxin Kong,Chuanqiang Wu,Huimei Duan,Dongjiang Yang
Improving the sulfur-resistance of low-temperature methane combustion catalysts is great important for industrial applications. Electronic engineering of catalyst active sites is effective in tuning the catalytic performance. Herein, IrPt 0.5 /TiO 2 catalysts with electron-rich Ir structures modulated by Pt exhibit excellent low temperature sulfur-resistance towards methane combustion. The integrated characterization coupled with density functional theory calculations reveal that the strong electronic interaction between Ir and Pt induces the formation of electron-rich Ir structures. The electron-rich Ir structures with more defective oxygen vacancy and better redox ability greatly boost the adsorption and activation of O 2 while suppress SO 2 adsorption on the catalyst surface, leading to excellent sulfur tolerance towards methane combustion. This work highlights a practical electronic engineering strategy to tune the electron structure of Ir active sites for the development of practical methane oxidation catalysts.
研究领域:
催化化学
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材料科学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL THERMODYNAMICS
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2019
·
IF 2.29
Jun-Feng Wang,Pan Liang
A pure barium borate of BaB 8 O 11 (OH) 4 ·3H 2 O has been synthesized and characterized by XRD, FT-IR, TGA, and chemical analysis. The molar enthalpies of solution of BaB 8 O 11 (OH) 4 ·3H 2 O in 1 mol dm −3 HCl(aq), and Ba(OH) 2 ·8H 2 O in the mixture solvent of {2.00 cm 3 of 1 mol·dm −3 HCl + H 3 BO 3 (aq)} were measured by microcalorimeter at T = 298.15 K, respectively. With the use of previously determined enthalpy of solution of H 3 BO 3 (s) in 1 mol·dm −3 HCl(aq), and the standard molar enthalpies of formation for Ba(OH) 2 ·8H 2 O(s), H 3 BO 3 (s), and H 2 O(l), the standard molar enthalpy of formation of −(7500.6 ± 6.5) kJ·mol −1 at T = 298.15 K was obtained based on an appropriate thermochemical cycle. Moreover, the molar enthalpy of formation of −6091.7 kJ mol −1 for [B 8 O 11 (OH) 4 ] 2− was estimated by a group contribution method, which was used to predict the Δ f H m o of a series of alkaline-earth metal borates for MB 8 O 11 (OH) 4 (M = Ca, Sr, Ba).
研究领域:
物理化学
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无机化学
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热化学
✓ 已验证
DOI
高影响因子
JOURNAL OF APPLIED MICROBIOLOGY
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2025
·
IF 3.2
Zhang Chuhan,Qin Lijun
AimsTo determine the optimum conditions for extracting Eucommia ulmoides gum (EUG) from Eucommia ulmoides leaves during fermentation by Coprinellus disseminatus. At the same time, the EUG characteristics were characterized.Methods and resultsThe ability of C. disseminatus to secrete degrading enzymes, including enzyme activity and lignocellulose content, was observed by culturing C. disseminatus on a medium with different formulations. Based on the optimal formula, the fermentation conditions were determined by an orthogonal test and EUG was extracted. After that, the characteristic parameters of EUG were determined by FT-IR, 1H-NMR, SEM, POM, DSC, XRD and GPC. The results showed that the lignin and hemicellulose contents in Eucommia leaves decreased significantly with the increase of fermentation days, and C. disseminatus mediated fermentation had an obvious damage effect on the tissue of Eucommia leaves. At the same time, At the same time, xylan can be used as an initiator to induce the expression of degradation-related enzymes. The extraction yield of EUG from Eucommia ulmoides leaves after fermentation was 3.06%, which was significantly improved. The optimum fermentation conditions were 4% inoculum, 28°C fermentation temperature, and pH = 5. The results of infrared FT-IR and 1H-NMR showed that the extract had typical characteristics of EUG, and the surface and quenching part of the EUG were smooth, as observed by SEM. In addition, DSC and XRD analysis show that there are two crystal types, α and β, in the crystallization process of molten EUG. The main crystallization type of EUG extracted from fermented leaves was β type.ConclusionThe ability of C. disseminatus to produce degrading enzymes can effectively improve the extraction rate of EUG under optimal fermentation process. The method can maintain the integrity of gutta-percha better. EUG has the characteristics of good crystallinity, many β crystal types and high molecular weight.
研究领域:
生物技术
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生物化学
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材料科学
·
植物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2024
·
IF 8.1
Meng-yuan Ding,Ming-ze Jia,Juan Wang
Green hydrogen production from methanol is a pivotal technology for energy transformation. In this work, the heterojunction structure of NiO–TiO 2 and incorporated Pd/Ir/Ru nanoparticles were successfully prepared through the utilization of sol-gel and in situ photodeposition methods. The highest yield of hydrogen from methanol is contributed by 0.5Pd–1Ni–TiO 2 showing 80.73 mmol g −1 H 2 for 4 h, which is 15.03 times higher than the H 2 yield obtained using TiO 2 . Furthermore, this work reveals that methanol adsorbs in two states: molecular CH 3 OH and dissociated CH 3 O∗, and the main adsorption modes of methanol on the surfaces of TiO 2 , 1Ni–TiO 2 and 0.5Pd–1Ni–TiO 2 exhibit similarities, with bridge adsorption being identified as the most favorable mode. The possible mechanism of the formation of main products was proposed. HCOOH is formed by oxidation of HCHO, or from desorption of formate. The two C–C coupling reactions of ·COOH + ·COOH and ·COOH + ·CH 3 produce CH 3 COOH.
研究领域:
材料科学
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催化化学
·
能源转化
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2022
·
IF 7.968
Hai-Fang Mao,Hong-Qing Fu,Ji-Bo Liu,Yun Zhao
A novel iron-pyridine-based chelate Fe-PYPA was synthesized via a facile and green strategy. The chelate served as a highly efficient catalyst toward CO 2 cycloaddition . A 95.7% PO conversion and a 98.4% PC selectivity were achieved under moderate conditions. Even under solvent-free conditions, Fe-PYPA could achieve a 93.6% conversion and 98.2% selectivity, acting as a robust and efficient catalyst toward CO 2 cycloaddition. Moreover, the as-prepared catalyst showed desirable catalytic activity , good recyclability , remarkable thermo-stability and ideal compatibility to a variety of epoxy substrates. In-situ ATR-IR spectroscopy was used as a powerful tool to gain process understanding for the whole conversion from CO 2 to cyclic carbonate under atmospheric pressure in the presence of TBAI. The process of PO’s ring opening, activation and insertion of CO 2 and the formation of cyclic carbonate were illuminated explicitly through the change of characteristic absorption peaks, providing direct and visual evidence for the mechanism proposed. The present work paves a new way for theoretical and experimental explorations on novel catalyst design and process understanding for highly-efficient greenhouse gas re-utilization.
研究领域:
化学工程
·
催化化学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
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