Nanoscale
·
2019
·Vol. 11
·期 42
·20301-20306
·
IF 6.97
Mingxing Gong,Jing Zhu,Mingjie Liu,Peifang Liu,Zhiping Deng,Tao Shen,Tonghui Zhao,Ruoqian Lin,Yun Lu,Shize Yang,Zhixiu Liang,Seong Min Bak,Eli Stavitski,Qin Wu,Radoslav R. Adzic,Huolin L. Xin,Deli Wang
Rational designing of catalysts to promote the sluggish kinetics of the cathode oxygen reduction reaction in proton exchange membrane fuel cells is still challenging, yet of crucial importance to its commercial application. In this work, on the basis of theoretical DFT calculations which suggest that order structured fct-phased PtFe (O-PtFe) with an atomic Pt shell exhibits superior electrocatalytic performance towards the ORR, the desired structure was prepared by using a scalable impregnation–reduction method. The as-prepared O-PtFe delivered enhanced activity (0.68 A mg−1Pt) and stability (73% activity retention after 10 000 potential cycles) compared with the corresponding disordered PtFe alloy (D-PtFe) and Pt. To confirm the excellent durability, in situ X-ray absorption fine structure spectroscopy was conducted to probe the local and electronic structure changes of O-PtFe during 10 000 cycle accelerated durability testing. We hope that this facile synthesis method and the in situ XAFS experiment could be readily adapted to other catalyst systems, facilitating the screening of highly efficient ORR catalysts for fuel cell application.
研究领域:
材料科学
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催化化学
·
能源技术
✓ 已验证
DOI
高影响因子
RARE METALS
·
2025
·
IF 11
Pan Jia-Xin,Zhao Long-Sheng,Li Zheng,Feng Zong-Yu,Liu De-Peng,Chen Jun,Huang Xiao-Wei
To achieve selective leaching of ion adsorption rare earth, it is necessary to thoroughly reveal the differences in the adsorption mechanisms of aluminum and rare earth elements. In this study, we investigated the adsorption processes of Dy and Al on the surface of K–homoionic kaolinite using batch experiments and sequential chemical extractions. The results revealed that the adsorption of Dy and Al, as well as the desorption of K, followed the Langmuir model. The maximum ion-exchangeable capacity of Dy was higher (9.39 mmol·kg −1 ) than that of Al (6.30 mmol·kg −1 ). The ion exchange stoichiometry ratios of Dy–K and Al–K derived from the Langmuir model were 2.0 and 2.6. The analysis of X-ray absorption fine structure (XAFS) and density functional theory (DFT) revealed that Dy and Al were adsorbed onto kaolinite as outer-sphere hydrated complexes via hydrogen bonds. Dy was adsorbed as [Dy(H 2 O) 10 ] 3+ , and Al was adsorbed as [Al(OH) 2 (H 2 O) 4 ] + . In particular, the adsorption of Al resulted in protonation of the hydroxyl groups on the surface of the kaolinite. Based on the above insights, the higher ion exchange stoichiometry ratios are attributed to closer adsorption distances (6.04 Å for Dy and 3.69 Å for Al) and lower adsorption energies (− 223.72 kJ·mol −1 for Dy and − 268.33 kJ·mol −1 for Al). The maximum ion-exchangeable capacity is related to the change of the surface electrical properties of kaolinite. The zeta potential was increased to − 7.3 mV as the protonation resulted from aluminum adsorption, while Dy adsorption had a minor effect, maintaining a value of − 17.5 mV. Graphical abstract
研究领域:
矿物学
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环境科学
·
理论化学
✓ 已验证
产品关联
DOI
高影响因子
Materials
·
2022
·Vol. 15
·期 9
·3031
·
IF 3.748
Shijing Zhao,Wenju Zhou,Xiaojun Xiang,Xuyan Cao,Ning Chen,Weifeng Chen,Xiaohui Yu,Bingmin Yan,Huiyang Gou
The precise determination of atomic position of materials is critical for understanding the relationship between structure and properties, especially for compounds with light elements of boron and single or multiple transition metals. In this work, the single crystal X-ray diffraction is employed to analyze the atomic positions of Co2MoB4and Fe2MoB4with a Ta3B4-type structure, and it is found that the lengths of B-B bonds connecting the two zig-zag boron chains are 1.86 Å and 1.87 Å, but previously unreported 1.4 Å. Co and Fe atoms occupy the same crystallographic position in lattice for the doped samples and the valence is close to the metal itself, and Co/Fe K-edge X-ray Absorption Fine Structure(XAFS) spectra of borides with different ratios of Co to Fe are collected to detect the local environment and chemical valence of Co and Fe. Vickers hardness and nano indentation measurements are performed, together with the Density Functional Theory (DFT) calculations. Finally, Co2MoB4possess better thermal stability than Fe2MoB4evaluated by Thermogravimetric Differential Thermal Analysis (TG-DTA) results.Keywords:transition metal boride;hardness;XAFS;thermal stability
研究领域:
材料科学
·
物理学
✓ 已验证
DOI
PubMed
高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2024
·
IF 10.8
Wanli Lian,Guanghui Yu,Jie Ma,Juan Xiong,Cuiyun Niu,Ran Zhang,Haijiao Xie,Liping Weng
Despite extensive study, geochemical modeling often fails to accurately predict lead (Pb) immobilization in environmental samples. This study employs the Charge Distribution MUlti-SIte Complexation (CD-MUSIC) model, X-ray absorption fine structure (XAFS), and density functional theory (DFT) to investigate mechanisms of phosphate (PO4) induced Pb immobilization on metal (hydr)oxides. The results reveal that PO4 mainly enhances bidentate-adsorbed Pb on goethite via electrostatic synergy at low PO4 concentrations. At relatively low pH (below 5.5) and elevated PO4 concentrations, the formation of the monodentate-O-sharing Pb-PO4 ternary structure on goethite becomes important. Precipitation of hydropyromorphite (Pb5(PO4)3OH) occurs at high pH and high concentrations of Pb and PO4, with an optimized log Ksp value of −82.02. The adjustment of log Ksp compared to that in the bulk solution allows for quantification of the overall Pb-PO4 precipitation enhanced by goethite. The CD-MUSIC model parameters for both the bidentate Pb complex and the monodentate-O-sharing Pb-PO4 ternary complex were optimized. The modeling results and parameters are further validated and specified with XAFS analysis and DFT calculations. This study provides quantitative molecular-level insights into the contributions of electrostatic enhancement, ternary complexation, and precipitation to phosphate-induced Pb immobilization on oxides, which will be helpful in resolving controversies regarding Pb distribution in environmental samples.
研究领域:
环境科学
·
地球化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Materials Chemistry A
·
2019
·Vol. 8
·期 6
·3145-3153
·
IF 10.733
Bing Liu,Rongli Cui,Huan Huang,Xihong Guo,Jinquan Dong,Huanli Yao,Ying Li,Dangui Zhao,Jiahao Wang,Jing Zhang,Yu Chen,Baoyun Sun
In this study, the stability mechanism of the optimized methyl ammonium lead triiodide (CH3NH3PbI3, MAPbI3)/[6,6]-phenyl-C61-butyric acid methyl ester (PCBM) perovskite active layer upon exposure to moisture, light, and heating was investigated. For the first time, the existence of high-valence lead arising from PCBM is confirmed by X-ray absorption fine spectroscopy (XAFS) based on synchrotron radiation, which helps to form stronger Pb–I bonds and facilitate carrier transport. Moreover, the degree of disorder of perovskites and the [PbI6]4− octahedral distortion are significantly improved, as well as the crystallization both on the surface and in the bulk. The result of this study provides a fundamental understanding of the functions of additives with electron-withdrawing properties (e.g., PCBM) in perovskite materials and could specifically be extended to systematically design and fabricate high-efficiency and stable solar cells.
研究领域:
材料科学
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光伏技术
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物理化学
✓ 已验证
DOI
高影响因子
iScience
·
2026
·Vol. 29
·期 6
·
IF 4.5
Ziyu Wang,Xuejie Han,Baohao Qian,Xiulai Zhang,Jingyuan Ma,Ru Feng,Meiqin Shi,Guangbo Chen,Fanfei Sun
Photothermal catalytic reduction of CO 2 to CO has been regarded as a promising strategy for solar-to-chemical energy conversion, yet the dynamic evolution of active sites under realistic reaction conditions remains poorly understood. Herein, we synthesized CuO/ZnO (CuZnO) catalysts with intimate interfacial contact via co-precipitation followed by calcination method. Under photothermal conditions, CuZnO underwent in situ reconstruction into low-coordinated metallic Cu in close contact with ZnO, delivering a CO generation rate of ∼18.1 mmol g −1 h −1 with a selectivity as high as 99% at 200 °C, outperforming that achieved under purely thermal conditions. Operando photothermal X-ray absorption fine structure (XAFS) spectroscopy revealed the real-time evolution of both Cu and Zn coordination environments in CuZnO, illustrating the formation and stabilization of metallic Cu on ZnO during photothermal catalysis. This study elucidates the mechanisms underlying photothermal synergy in CO 2 reduction and provides mechanistic insights into active-site dynamics under photothermal conditions.
✓ 已验证
DOI
PubMed
高影响因子
Water Science and Engineering
·
2023
·
IF 4
Xiao-jie Guo,Wei-kang Fu,Jing-yuan Ma,Bo-jun Xi,Chen Wang,Meng-yao Guan
Lignocellulose has the potential to become a bio-based adsorbent due to its biodegradability and renewability. In this study, a novel polydopamine-functionalized-lignin (lignin@PDA), prepared via self-polymerization of dopamine (PDA) on lignin, was used as a bio-based adsorbent for rapid scavenging of hexavalent chromium (Cr(VI)). The morphology, functional groups, crystalline structure, and chemical composition of lignin@PDA were characterized with a scanning electron microscope–energy dispersive spectrometer, Fourier transform infrared spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The Cr(VI) adsorption process of lignin@PDA was studied using batch experiments as a function of pH, ionic strength, adsorbent dose, and contact time at room temperature. The adsorption rate of lignin@PDA was five times greater than that of the unmodified lignin, with a maximum adsorption capacity of 102.6 mg/g in an acidic medium. The adsorption of Cr(VI) on lignin@PDA fit the pseudo-second-order equation and the Freundlich model, indicating that the adsorption process was mainly dominated by chemisorption and surface complexation. The thermodynamic parameters showed that adsorption of Cr(VI) on lignin@PDA was an endothermic and spontaneous process. The X-ray absorption fine structure results showed that sorption and reduction of Cr(VI) into Cr(III) occurred simultaneously on lignin. Moreover, PDA coating not only improved the reactivity of lignin but also promoted the complete reduction of Cr(VI) by lignin. According to these results, polydopamine-functionalized-lignin is a promising bio-based adsorbent for immobilization of Cr(VI) from wastewater.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Xingyue Yang,Lei Wang,Shijie Zhou,Shilong Zhang,Yongfang Xu,Yujie Bian,Zhaowei Tian,Yusen Yang,Min Wei
Liquid organic hydrogen carriers (LOHC), which involve reversible catalytic hydrogenation/dehydrogenation cycles, have attracted considerable attention. This study investigates Cu/CuAlO x catalysts with unique Cu 0 –Cu + interfacial sites, which are prepared via structural topological transformation of layered double hydroxide (LDH) precursors. The optimized Cu/CuAlO x catalysts exhibit exceptional catalytic activity in 1,2,3,4-tetrahydroquinoline (THQ) dehydrogenation, achieving a complete conversion of THQ within 1.5 h and a turnover frequency (TOF) value amounts to 19.94 h −1 at 150 °C, which stands at the highest echelon compared with previously reported heterogeneous catalysts. Furthermore, the catalyst also exhibits excellent performance in quinoline hydrogenation (yield >99 %) after 6 h at 60 °C, and the TOF value reaches up to 7.01 h −1 . A comprehensive investigation based on XPS, TEM and XAFS verifies the dual active states Cu 0 and Cu + sites coexisting on nanoparticle surfaces. Both experimental studies ( in situ DRIFTS and XPS) and DFT calculations reveal the pivotal role of the Cu 0 − Cu + synergistic effect in dictating catalytic behavior: the Cu + species preferentially adsorb and activate the N − H bonds and C − H bonds in N-heterocycles; Whereas the Cu 0 site facilitates efficient reassociation of surface adsorbed H atoms and product desorption (H 2 ). This work exhibits substantial potential for implementation in hydrogen storage technologies, offering a viable pathway towards efficient LOHC utilization in clean energy systems.
研究领域:
催化化学
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材料科学
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氢气储存
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化学反应工程
·
表面化学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2025
·
IF 7.2
Han Cui,Xuejiao Wu,Yuchen Wang,Yafei Zhang,Juan Luo,Dandan Zhou
This study investigates the migration of lead (Pb) during soil electrokinetic remediation (EKR) with sodium alginate (SA), providing important data on ion orientation and Pb removal efficiency. A 1 mV/cm voltage was applied to kaolinite contaminated with Pb²⁺, and SA was applied to regulate Pb migration. Pb was detected in both the anolyte and catholyte, with varying molar Pb/C ratios. In the anode and cathode chambers, the molar ratios reached 1:7.79 and 1:2.64, respectively. The addition of Pb 2+ disrupted the stable structure of SA, and density functional theory (DFT) calculations combined with X-ray Absorption Fine Structure (XAFS) analysis showed that Pb²⁺ forms dual-ridentate (positively charged) and quad-/hexaridentate (negatively charged) complexes with SA, thereby influencing Pb migration toward the corresponding electrodes. Additionally, Pb in the soil transformed into immobile particulate states, such as PbO 2 , Pb 3 O 4 , and PbO. The formation of these particulate phases and conversion of mobile Pb phases to the anode reduced the Pb migration ability at the cathode. These findings offer fresh perspectives on EKR’s application for heavy metal soil remediation, particularly six-period metals on the periodic table, improving our understanding of Pb behavior during electrokinetic treatments.
研究领域:
环境科学
·
土壤化学
·
电化学
·
重金属修复
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材料科学
·
地球化学
✓ 已验证
产品关联
DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2021
·
IF 5.455
Yanliang Zhai,Yunshan Shang,Luoming Zhang,Xiaoling Meng,Yanjun Gong,Lirong Zheng,Jing Zhang,Ping Liu
Hydrothermally modified nanosheet ZSM-5 zeolite by directly using MnO x nanoparticles was carried out and this substantially offered a high performance catalyst for methanol to propylene (MTP) reaction. The properties of as synthesized ZSM-5 nanosheets with different MnO x amounts (NS-x) were compared with ZSM-5 nanosheets modified by impregnation method (IM-0.5) and physically mixed method (PM-0.5), respectively. The initial state of MnO x nanoparticles was close to Mn 2 O 3 with 20 nm in size. XRD , H 2 -TPR and XAFS results confirmed under high temperature hydrothermal condition, the Mn 2 O 3 nanoparticles disaggregated into Mn 2 O 3 clusters and entered the framework defects of nanosheet zeolite with high dispersion. Infrared spectra of hydroxyl groups (OH-IR) showed that the Mn 2 O 3 clusters were bonded with silanol defects both on the surface and inside zeolite, which substantially increased the stability of Mn 2 O 3 clusters and healed the framework defects. In contrast, the Mn species in the impregnated sample was close to the co-existence of Mn 2+ ions and MnO 2 nanoparticles with 2–3 nm, no interaction between Mn species and Si–OH group was determined. Notably, the typical sample (NS-0.5) with MnO x cluster modification performed much higher propylene selectivity and catalytic stability (~52%, 240 h, WHSV = 3 h −1 ), while the conventional IM-0.5 and PM-0.5 showed poor propylene selectivity (48%, 46%) and catalytic stability (166 h, 133 h) in MTP reaction. The excellent result should be attributed to the subtle control of external strong acid and the less structural defects, due to specific existence of bonded Mn 2 O 3 clusters.
研究领域:
化学
·
材料科学
·
催化
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）