CHINESE JOURNAL OF CHEMISTRY
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2022
·Vol. 40
·期 9
·1045-1052
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IF 5.56
Kui Wang,Guo-Jie Gao,Xiao-Yan Wang
Comprehensive Summary In this work, a spherical calixpyridinium–IR-820 supramolecular assembled material was fabricated based on the calixpyridinium- induced IR-820 aggregation. This assembled material exhibited a well visible light responsiveness by the photodecomposition of aggregated IR-820 accompanied by an obvious color change. Such photochromic material has many potential applications. More interestingly, the photodecomposition of aggregated IR-820 was significantly promoted, although the aggregated photosensitizers usually exhibited a lower photoreactivity. This approach can be further extended to construct various visible-light responsive supramolecular assembled materials and potentially applied in many fields. Herein, benefitting from the pH-dependent luminescent properties of calixpyridinium and the photodegradation products of IR-820, a pH-controlled visual multicolor luminescence was achieved, which was perfectly applied in the detection of pH from 5 to 10 by naked eyes.
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CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Yixi Wang,Wenqing Xu,Chaoqun Li,Yang Yang,Zanbu Geng,Tingyu Zhu
Gaseous ammonia (NH 3 ), especially that emitted from selective catalytic reduction with NH 3 (NH 3 –SCR) units in the atmosphere is potentially harmful to both human health and the environment. The noble metal catalytic oxidation technology placed behind the SCR unit has been considered to be a promising method for decreasing NH 3 slip. In this study, we prepared Ir/Al 2 O 3 catalysts using two different crystal structures of Al 2 O 3 (α–Al 2 O 3 or γ–Al 2 O 3 ) as supported by an impregnation method and evaluated the performance of the selective catalytic oxidation of NH 3 (NH 3 –SCO). We found that the Ir/γ–Al 2 O 3 catalyst performed better than the Ir/α–Al 2 O 3 catalysts, with 99% of NH 3 converted at 260 °C. The X–ray absorption fine structure revealed that the active species on the Ir/Al 2 O 3 catalysts are mainly oxidized IrO 2 . High–angle annular dark–field images of aberration–corrected scanning transmission electron microscopy revealed that IrO 2 species over 1 nm in diameter are beneficial for activity. In situ diffuse reflectance for infrared Fourier transform spectroscopy studies suggested that the differences in NH 3 –SCO activity were caused by the activity of reactive oxygen species, and the formation of –NH 2 may be the decisive step of the NH 3 oxidation reaction.
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ACS Catalysis
·
2021
·
IF 13.084
Li Sun,Junkang Xu,Xiaoyan Liu,Botao Qiao,Lin Li,Yujing Ren,Qiang Wan,Jian Lin,Sen Lin,Xiaodong Wang,Hua Guo,Tao Zhang
Single-atom catalysts (SACs) with complete dispersion of metal species on substrates provide the ultimate atom economy and opportunities for improved heterogenous catalysis or to develop more catalyst formulation. However, atomically dispersed dopants can also improve the catalyst in an indirect capacity. Here, we report an Ir1/α-MoC SAC that exhibits high activity for water gas shift reaction with ∼100% CO conversion at 150 °C. The reaction rate of this catalyst is orders of magnitude higher than previous Ir-based catalysts and ∼4 times that of α-MoC. Experimental characterizations combined with density functional theory (DFT) calculations reveal that such good performance originates from the effective catalysis by the α-MoC substrate with Ir1 serving as a single-atom promoter. DFT calculations also establish a correlation between the active Mo sites and the catalytic performance for water gas shift reaction. This work highlights the possibility of enhancing catalysis by single-atom promoters as a promising strategy for designing effective SACs.
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ACS Catalysis
·
2021
·
IF 13.084
Chenyang Shen,Kaihang Sun,Zhitao Zhang,Ning Rui,Xinyu Jia,Donghai Mei,Chang-jun Liu
Iridium (Ir) catalysts have been extensively applied in homogeneous and photocatalytic CO2 conversion. However, CO2 hydrogenation to methanol over the supported Ir catalyst in a heterogeneous flowing reactor has not been reported yet. Here, we report that indium oxide supported Ir catalyst (Ir/In2O3) of high dispersion is very active for CO2 hydrogenation to methanol. Compared to In2O3, Ir/In2O3 shows a significantly higher activity with even higher methanol selectivity. For example, CO2 conversion of 17.7% is achieved on Ir/In2O3 of 10 wt % Ir loading with methanol selectivity over 70% and high methanol space time yield of 0.765 gMeOH h–1 gcat–1 at 4/1 of the CO2/H2 feed ratio, 21 000 h–1, 300 °C, and 5 MPa. With the catalysts tested, the higher Ir loading causes the higher activity. The catalyst characterization confirms an intense interaction between iridium and In2O3, which causes the high dispersion of the Ir catalyst with the Ir–In2O3 interface as the active site for selective hydrogenation of CO2 into methanol. The Ir loading not only enhances the formation of oxygen vacancies but also stabilizes the vacancies for improved CO2 activation. Further density functional theory studies reveal that the reverse water–gas shift route is more favorable over the formate route for CO2 hydrogenation to methanol over Ir/In2O3 catalyst.
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MATERIALS RESEARCH BULLETIN
·
2020
·
IF 4.019
Jingru Wang,Shanhui Zhu,Yunwei Wang,Yingyong Wang,Guoqiang Jin,Xili Tong,Xiangyun Guo
The hydrogenation of levulinic acid (LA) to γ-valerolactone (GVL) under mild condition is a promising but challenging process. Herein, SiC supported Ru-Ir bimetallic catalyst exhibit enhanced catalytic activity for aqueous hydrogenation of LA into GVL under mild conditions. Comparing with monometallic Ir 3 /SiC and Ru 3 /SiC, the conversion of LA over bimetallic Ru 0.5 -Ir 2.5 /SiC catalyst increase from 51.2 % and 45.9% to 100% at 25 °C and 0.2 MPa of H 2 pressure. The enhanced catalytic activity of Ru 0.5 -Ir 2.5 /SiC catalyst originates from the electronic synergistic effect among Ru, Ir and SiC. Due to the electron transfer, electron-richened Ir nanoparticles show stronger ability for H 2 dissociation, and the SiC surface produces more active sites to accommodate hydrogen species that spill over from Ir and Ru. The adsorption and hydrogenation of LA molecules occur on the surface of SiC.
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APPLIED CATALYSIS B-ENVIRONMENTAL
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2020
·
IF 16.683
Guangxia Jin,Jie Liu,Chan Wang,Wenxiu Gu,Guoxia Ran,Bing Liu,Qijun Song
An enzyme-like nanoplatform obtained from sodium citrate-modified iridium nanoparticles (Cit-IrNPs) was presented, which exhibits excellent peroxidase, catalase and oxidase like activities thanks to the large accessible surface area and high-index facets of the mono-dispersed nanoparticles. The morphology and structures of Cit-IrNPs were comprehensively characterized by TEM, HRTEM, XRD, IR and XPS. The surface chemistry of Cit-IrNPs reveals that the oxidase-like and peroxidase-like activities can be ascribed to the formation of O 2 ¯ from the activation of dissolved oxygen on the high-index facets of IrNPs. The oxidase-like activity of Cit-IrNPs was further manifested by the oxidation of 33.3 mM aromatic alcohols in the presence of 3 mg/mL Cit-IrNPs in ambient conditions. Over 90 % conversion rates were readily obtainable in 10 h for all the tested alcohols with an initial reaction rate of ca. 20 μmol/h. More significantly, apart from the aldehydes no other byproducts were detected. The kinetic analysis of the enzyme mimic suggests the reaction follows a classical Michaelis-Menten model. The enzyme mimic also shows a good stability, as no obvious decrease in catalytic activity was observed after recycled use for 6 times. Furthermore, DFT calculation was employed to elucidate the reaction mechanism and it was found that the alcohol is initially bond to Ir(0) and subsequently forms Ir δ + -alkoxide species and the carbonyl product. Meanwhile, the Ir δ + -hydride species reductively eliminates O 2 ¯ and returns back to Ir(0). To the best of our knowledge, this is the first report of metal nanomaterials which can effectively transform aromatic alcohols to corresponding aldehydes at ambient conditions without need of external energy input.
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ACS Omega
·
2020
·
IF 2.87
Yan Ji,Xiaoliang Yang,Zhi Ji,Linhui Zhu,Nana Ma,Dejun Chen,Xianbin Jia,Junming Tang,Yilin Cao
The infrared spectrum (IR) characteristic peaks of amide I, amide II, and amide III bands are marked as amide or peptide characteristic peaks. Through the nuclear magnetic resonance study, N-methylacetamide has been determined to have six fine components, which include protonation, hydration, and hydroxy structures. Then the independent IR spectrum of every component in N-methylacetamide is calculated by using the density functional theory quantum chemistry method, and the contribution of each component to amide I, II, and III bands is analyzed. The results of this research can help to explain the formation of the amide infrared spectrum, which has positive significance in organic chemistry, analytical chemistry, and chemical biology.
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PubMed
高影响因子
MOLECULES
·
2022
·Vol. 27
·期 21
·7431
·
IF 4.927
Caimei Zhang,Wenjuan Zhang,Yiran Wu,Bo Peng,Chunyuan Tian,Feng Luan,Wen Sun,Xuming Zhuang,Lijun Zhao
With several major polarity and weak optical properties, the sensitive detection of HCOOH remains a major challenge. Given the special role of HCOOH in assisting in the catalytic hydrogenation process of Ir complexes, HCOOH (as a hydrogen source) could rapidly activate Ir complexes as catalysts and further reduce the substrates. This work developed a facile and sensitive HCOOH fluorescence sensor utilizing an optimal catalytic fluorescence generation system, which consists of the phenyl-pyrazole-type Ir-complex PP-Ir-Cl and the coumarin-type fluorescence probe P-coumarin. The sensor demonstrates excellent sensitivity and specificity for HCOOH and formates; the limits of detection for HCOOH, HCOONa, and HCOOEt3N were tested to be 50.6 ppb, 68.0 ppb, and 146.0 ppb, respectively. Compared to previous methods, the proposed sensor exhibits good detection accuracy and excellent sensitivity. Therefore, the proposed HCOOH sensor could be used as a new detection method for HCOOH and could provide a new design path for other sensors.Keywords:HCOOH detection;Ir complexes;catalytic hydrogenation;fluorescence probe
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JOURNAL OF CATALYSIS
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2019
·
IF 7.723
Huan Liu,Lei Liu,Wen-Di Guo,Yong Lu,Xiao-Li Zhao,Ye Liu
The complexation of IrCl 3 ⋅3H 2 O with the electron-deficient phosphines ( L1 - L6 ) respectively afforded a bi-functional catalyst possessing the dual functions of transition metal complex (Ir III -P) and Ir III -Lewis acid for tandem hydroformylation-acetalization of olefins. The best result was obtained over L5 -based IrCl 3 ⋅3H 2 O catalytic system which corresponded to 97% conversion of 1-hexene along with 92% selectivity to the target acetals free of any additive. The crystal structure of the novel Ir III -complex of Ir III -L4 indicated that the electron-deficient nature of the involved phosphine warranted Ir-center in +3 valence state without reduction, which served as the Lewis acid catalyst for the subsequent acetalization of the aldehydes as well. Moreover, as an ionic phosphine, L6 -based IrCl 3 ⋅3H 2 O system immobilized in RTIL of [Bmim]PF 6 could be recycled for 6 runs without the obvious activity loss or metal leaching.
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2017
·Vol. 24
·期 33
·25881-25888
·
IF 2.741
Kang Xiaolei,Sun Wei,Cao Limei,Yang Ji
A novel cryptomelane-Ir (cry-Ir) electrode is prepared for Ir to enter into the cryptomelane (named as cry-Mn) structure and used for aspirin degradation. This catalyst can efficiently reduce the Ir usage from 85 to 34%. Also, the onset potential of cry-Ir is about 1.40 V and the over potential is about 0.34 V at 10 mA cm −2 , indicating that cry-Ir has an excellent oxygen evolution reaction (OER) activity to produce oxidizing species and can decrease electrolytic voltage during the electro-oxidation process. So, the electrical efficiency per log order (EE/O) for cry-Ir electrode is only 5% of PbO 2 electrode, which is the best electrode for organic degradation. Also, cry-Ir has large tunnel size which favors insertion of aspirin molecule into cry-Ir structure and enhances the contact between reactive intermediates and the contaminant. Using cry-Ir as anode, 100% aspirin removal and 55% chemical oxygen demand (COD) removal could be obtained at 4 V. We also compare cry-Ir electrode with IrO 2 and find that IrO 2 anode can only eliminate 20% aspirin under the same condition. As a result, cry-Ir is a promising anode material for organic pollutant degradation.
Aspirin removal after 4h under different voltages. Aspirin removal on IrO 2 /Ti-f and cry-Ir/Ti-f after 4h.
研究领域:
环境科学
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材料科学
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化学工程
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Journal of Materials Chemistry A
·
2024
·Vol. 12
·期 25
·15386-15397
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IF 10.7
Qi Zhang,Peiyao Pan,Xuewen Xia,Shujuan Wang,Zhongya Pang,Guangshi Li,Li Ji,Xing Yu,Xionggang Lu,Xingli Zou
Constructing multiple nanosized heterogeneous structures with an in situ optimized coordination environment for dispersing and stabilizing noble metal single atoms (SAs) is a highly effective strategy for high-efficiency utilization of SAs and improving the electrocatalytic performances of the oxygen evolution reaction (OER). Herein, a multi-crystalline-amorphous heterogeneous composite (CoP2@CN–Ir(200)) composed of crystalline CoP2, amorphous CoOx and amorphous N-doped carbon was constructed for in situ loading of Ir SAs by cyclic voltammetry (CV) electrodeposition in an ionic liquid. By precisely controlling the electrodeposition cycles, the loading matrix of Ir SAs was simultaneously reconstructed and optimized. Some of the crystalline CoP2 is transformed into amorphous CoOx with activated high-valence Co; a coordination environment toward oxygenated species is built with more lattice oxygen and stronger adsorption ability of oxygen; the abundant heterointerfaces and the enhancement of the oxidation state disperse and stabilize Ir atoms in the form of OER-favorable high-valence Ir3+/Ir4+ by covalent Ir–O bonds (including Ir–O–Co bonds). As a result, abundant active sites with high intrinsic activity are exposed, and an accelerated charge transfer rate can be achieved, endowing CoP2@CN–Ir(200) with an outstanding electrocatalytic activity. Ultralow overpotentials of 189 and 300 mV at 10 and 100 mA cm−2, respectively, are achieved with a small Tafel slope of 36.9 mV dec−1, surpassing most reported remarkable Ir-related catalysts.
研究领域:
材料科学
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电化学
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催化科学
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ACS Catalysis
·
2025
·
IF 13.1
Jialong Dai,Zhiwei Zhao,Fuhou Tian,Xianzhou Wang,Xiaogang Yu,Bo Liu,Dan Yang,Xupeng Zong,Yu Tang,Fei Wei,Yanhui Yang,Yihu Dai
The synergistic catalysis between the active metal site and the oxide support is crucial for catalytic dry reforming of methane (DRM); however, the specific roles of hydroxyl groups at the metal–oxide interface have been particularly elusive. To probe this, Ir/Al2O3 model catalysts (Ir/Al2O3-400R and Ir/Al2O3-650R reduced at 400 and 650 °C, respectively) were constructed with isolated Ir sites but distinct hydroxyl properties. Both catalysts exhibited high activity and coke-resistant stability in long-term DRM reactions at 650 °C. By a combination of structure characterizations, kinetic analyses, and in situ isotopic spectral techniques, their catalytic performances are correlated with the hydroxyl structures. The surface hydroxyls are directly involved in CH4 and CO2 dissociation pathways, and specifically, the triply bridged hydroxyl (μ3-OH), a strong proton donor, cooperates with the Ir metal site to achieve decoupled CH4 dissociation. Beyond this synergistic effect, a complete cycle of hydroxyl conversion and regeneration is integral to the DRM mechanism. These findings offer a mechanistic perspective on the catalytic roles of hydroxyls in CH4 dissociation and dry reforming.
研究领域:
催化化学
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材料化学
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表面科学
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多相催化
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能量转换
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