CATALYSIS LETTERS
·
2020
·Vol. 151
·期 6
·1810-1820
·
IF 2.482
Zhao Nannan,Wang Songbo,Cheng Penggao,Zhang Jianping,Zhang Lei,Du Wei,Tang Na
Co 3− x Mn x O 4 is a bimetal oxide with excellent electrochemical activity in alkaline solution, has been regarded as a promising alternative in the field of ion-air batteries and proton exchange membrane fuel cell (PEMFC). Herein, we report a simple solvothermal-calcination method to fabricate Co 3− x Mn x O 4 with tunable external Co 3+ /Co 2+ and Mn 3+ /Mn 2+ ratio. The tunable ratio of element valence in the bimetal results in a higher exposure of active center for oxygen redox reaction (ORR), and thus lead to a better ORR activity, which was confirmed by X-ray photoelectron spectroscopy characterizations and electrochemical measurements. Specially, Co 1.8 Mn 1.2 O 4 with a Co 3+ /Co 2+ ratio of 2.08 showed an overpotential of 0.37 V at benchmark ORR current density of 3 mA/cm 2 in 0.1 M KOH, which is lower than that of pure oxide (Mn 3 O 4 0.53 V and Co3O4 0.56 V). In addition, the as prepared Co 1.8 Mn 1.2 O 4 exhibited a positive half-wave potential (0.83 V vs RHE) due to their more active sites, promotes charge transfer, adsorption and desorption of oxygen species. This work provides a strategy for the design and fabrication of earth-abundant, low-cost electrocatalysts for PEMFC in practical applications. Graphic Abstract Co 3− x Mn x O 4 was fabricated by tuning external Co 3+ /Co 2+ and Mn 3+ /Mn 2+ ratio, and the activity initially shows a positive correlation with the ration of Co 3+ /Co 2+ in Co 3− x Mn x O 4 .
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
Materials
·
2018
·Vol. 11
·期 5
·791
·
IF 2.467
Junping Ding,Huanchun Wang,Haomin Xu,Lina Qiao,Yidong Luo,Yuanhua Lin,Cewen Nan
High efficiency photocatalyst Bi2O2(CO3)1−xSxwas synthesized conveniently with chemical bath precipitation using Bi2O2CO3as the precursor. The microstructures of the samples are systematically characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS) and UV-Vis spectroscopy; the optical and photocatalytic properties are carefully tested as well. The content ofS, which was tuned through the controlling of the precipitation process, was verified to have an intense effect over the photocatalytic properties. A nearly saturatedSratio and the best photocatalytic performance were observed in specimens with the mostScontent. Our study reveals that, with negligible influence of the morphology and crystal structure, Bi2O2(CO3)1−xSxpossessed a broadened optical absorption regionfromultraviolet to visible light, and enhanced photocatalytic activity in comparison to precursor Bi2O2CO3in photocatalytic degradation of Congo Red aqueous solution.Keywords:Bi2O2CO3;Bi2O2(CO3)1−xSx;broadband spectra;photocatalysis
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF MOLECULAR STRUCTURE
·
2021
·
IF 3.196
Jiongquan Chen,Zhihua Yang,Kui Wu,Yun Yang,Shilie Pan
A new mixed borate and carbonate Sr 5 (CO 3 ) 2 (BO 3 ) 2 , which is isostructural with Ba 4 M(BO 3 ) 2 (CO 3 ) 2 (M = Ba, Sr), has been synthesized by hydrothermal method . It crystallizes in Pnma (No. 61) space group with the lattice parameters a = 7.387(4), b = 16.556(9) and c = 8.971(5) Å ( Z = 4). This structure features a three-dimensional (3D) network including SrO 8 polyhedra, isolated BO 3 and CO 3 triangles. UV-Vis-NIR diffuse reflectance spectrum for Sr 5 (CO 3 ) 2 (BO 3 ) 2 indicates that it has a deep ultra-violet cut-off edge of 190 nm. In addition, crystal structural comparison among mixed borates and carbonates shows that the interaction between boron-oxide groups and CO 3 groups leads to different arrangements of anionic groups, which can be classified into three types according to the connection of boron-oxide groups. An analysis of theoretical calculations based on density functional theory was also performed to understand the relationships between the structures and properties.
研究领域:
材料科学
·
化学
✓ 已验证
DOI
高影响因子
INORGANIC CHEMISTRY
·
2024
·
IF 4.3
Yuan Lin,Rong-Fang Zhang,Yucheng Hao,Ming-Yang Cao,Xuanlin Pan,Jiang-Gao Mao
Carbonates are ideal birefringent materials because their π-conjugated [CO3] groups are beneficial for large anisotropy. How to maximize the birefringence and maintain a wide transmittance simultaneously in carbonates is a great challenge. Adopting a multiple-functional group synergy strategy by combining alkaline-earth metal Ba2+ with large ion radius, PbO6F distorted hexagonal pyramid, and paralleled π-conjugated CO3 triangles together, we synthesized a new metal carbonate crystal, BaPb2(CO3)2F2. BaPb2(CO3)2F2 features a typical two-dimensional layered structure, which consists of a PbCO3F monolayer parallel to the ab plane and Ba2+ cations filled between the monolayers. BaPb2(CO3)2F2 exhibits a large experimental birefringence of approximately 0.245@546 nm and a short ultraviolet absorption edge down to 264 nm (Eg = 4.70 eV), indicating that it is a promising ultraviolet birefringent material. The reported highest experimental birefringence index among carbonate crystals is surpassed by BaPb2(CO3)2F2. The theoretical calculation shows that the contribution percentages for total birefringence are 57 and 43% for the CO3 group and PbO3F group, respectively. Our work offers a new route for designing new birefringent materials with excellent comprehensive performance.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Energy Chemistry
·
2024
·
IF 14
Fengli Wei,Jinghao Shen,Jiayin Xie,Zuyang Luo,Luyan Shi,Tayirjan Taylor Isimjan,Xiulin Yang,Jieshan Qiu,Bin Wu
Understanding and manipulating the structural evolution of water oxidation electrocatalysts lays the foundation to finetune their catalytic activity. Herein, we present a synthesis of NiSe 2 -Ce 2 (CO 3 ) 2 O heterostructure and demonstrate the efficacy of interfacial Ce 2 (CO 3 ) 2 O in promoting the formation of catalytically active centers to improve oxygen evolution activity. In-situ Raman spectroscopy shows that incorporation of Ce 2 (CO 3 ) 2 O into NiSe 2 causes a cathodic shift of the Ni 2+ →Ni 3+ transition potential. Operando electrochemical impedance spectroscopy reveals that strong electronic coupling at heterogeneous interface accelerates charge transfer process. Furthermore, density functional theory calculations suggest that actual catalytic active species of NiOOH transformed from NiSe 2 , which is coupled with Ce 2 (CO 3 ) 2 O, can optimize electronic structure and decrease the free energy barriers toward fast oxygen evolution reaction (OER) kinetics. Consequently, the resultant NiSe 2 -Ce 2 (CO 3 ) 2 O electrode exhibits remarkable electrocatalytic performance with low overpotentials (268/304 mV @ 50/100 mA cm −2 ) and excellent stability (50 mA cm −2 for 120 h) in the alkaline electrolyte. This work emphasizes the significance of modulating the dynamic changes in developing efficient electrocatalyst.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL PAPERS
·
2019
·Vol. 73
·期 7
·1761-1766
·
IF 1.246
Zhang Li-hui,Zhou Yan-biao,Li Wei-li,Zhao Xu-yao,Wang Ya-bo
Lu(OH)CO 3 :Ln 3+ /LuBO 3 :Ln 3+ (Ln = Eu, Tb) nanospheres have been synthesized by the soft chemistry route. This synthesis process does not require the addition of any organic solvents and surfactant. The whole process consists of homogeneous precipitation and hydrothermal process. First, uniform spherical Lu(OH)CO 3 :Ln 3+ (Ln = Eu, Tb) nanoparticles with the sizes of 70 nm were obtained by the classic urea-based homogeneous precipitation. Then, with the above Lu(OH)CO 3 :Ln 3+ (Ln = Eu, Tb) nanosphere as the precursor, the composites of Lu(OH)CO 3 :Ln 3+ /LuBO 3 :Ln 3+ (Ln = Eu, Tb) nanospheres formed by the simple hydrothermal process. The phases, morphologies, as well as the luminescence properties of as-prepared samples were characterized by means of X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, and photoluminescence. Under a short wavelength excitation, the down-conversion Eu 3+ and Tb 3+ -doped LuBO 3 samples were investigated and explained.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2015
·
IF 4.504
Mingshu Xiao,Dazhang Yang,Yuhua Yan,Yanping Tian,Mao Zhou,Meifeng Hao,Rui Cheng,Yuqing Miao
The Co 3 (VO 4 ) 2 multilayer nanoplates [Co 3 (VO 4 ) 2 -MNs] and Co 3 (VO 4 ) 2 ultrafine particle-comprised nanospheres [Co 3 (VO 4 ) 2 -UPNs] were prepared for the oxygen evolution reaction (OER). They are synthesized by a simple hydrothermal reaction using ethylenediaminetetraacetic acid and polyvinyl pyrrolidone as dispertants and pretectants. With the help of multi-walled carbon nanotubes (MWCNTs), the Co 3 (VO 4 ) 2 -MNs and Co 3 (VO 4 ) 2 -UPNs were immobilized respectivtly onto the surface of glassy carbon electrodes (GCEs). By comparison, the GCE–Co 3 (VO 4 ) 2 -MN/MWCNT exhibits higher performance of OER electrocatalysis and better stablity than the GCE–Co 3 (VO 4 ) 2 -UPN/MWCNT in the alkali electrolyte of 1 M KOH due to its higher surface roughness. The high surface free energy of Co 3 (VO 4 ) 2 -MNs is helpful for their immobilization on elelctrode surface, leading a better stability. The work shows that the noble metal-free electrocatalysts can lower the energy barrier and improve the energy efficiency for electrochemical water splitting to generate hydrogen.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2020
·
IF 6.182
Zewei Hao,Pengkun Wei,Yang Yang,Jingyu Sun,Yunhua Song,Donggang Guo,Lu Liu
Eminent OER electrocatalysts occupies a vital position for hydrogen produced from water splitting. Up to now, sulfides with spinel structure have been considered as the most promising electrocatalysts to replace noble metal catalysts, but generally their catalytic activities are still unsatisfactory. Based on above situation, we used one-step solvothermal method to synthesis two CuCo 2 S 4 nanosheets by introducing two different surfactants. Two CuCo 2 S 4 nanosheets both show outstanding catalytic properties for OER. Specifically, CuCo 2 S 4 CNS exhibits the best OER performance with a low overpotential of 269 mV at a current density of 10 mA cm −2 and a small Tafel slope of about 41 mV dec −1 in 1.0 M KOH. The CV scanning and chronoamperometry tests also show its excellent stability. XPS analysis reveals the introduction of Cu ions into Co 3 S 4 lattice improve the relative concentration of Co 3+ on CuCo 2 S 4 nanosheets surface, which makes the catalytic performance get extensively improvement.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
OPTICAL MATERIALS
·
2021
·
IF 3.08
Dechuan Li,Gungping Zhu,Xuelian Zhao
KTb(CO 3 ) 2 :Eu 3+ phosphors with intense stokes emission were synthesized by hydrothermal method . Under the excitation of 368 nm light, the pure KTb(CO 3 ) 2 shows an intense green emission at 543 nm corresponding to the 5 D 4 → 7 F 5 transition of Tb 3+ , about 5 times higher than that of the K + -free Tb 2 O(CO 3 ) 2 phosphor. As the Tb 3+ is partly substituted by Eu 3+ , the luminescence color can be transformed from green to red. The intensity of red emission of KTb(CO 3 ) 2 :Eu 3+ could greatly increase as the contents of Eu 3+ without any concentration quenching. Under the excited by 368 nm near-ultraviolet, the quantum efficiencies of KTb(CO 3 ) 2 and KTb(CO 3 ) 2 :0.3Eu 3+ were 93% and 80%, respectively. The high quantum efficiency shows that KTb(CO 3 ) 2 :Eu 3+ is a useful color-tunable luminescence material under excitation of ultraviolet light in the anti-counterfeiting, lighting and display.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2022
·
IF 7.139
Guangkai Guo,Dazhong Zhong,Tao Zhao,Guang Liu,Jinping Li,Qiang Zhao
In recent years, transition metal catalysts due to their low price, excellent conductivity and high activity have been extensively studied in OER . It is worth noting that Co 3+ plays a vital role in the process of oxygen evolution catalysis, because Co 3+ ions are considered to be active sites. The development of catalysts with high Co 3+ content has important application prospects for improving water oxidation efficiency. This paper uses a simple ligand-assisted synthesis method to promote the transformation of two-dimensional layered double hydroxides (LDHs) into two-dimensional metal organic frameworks (MOFs). MOF-OH/NF are quickly and easily prepared by electrooxidation , which exhibit superior OER properties, with a low overpotential of 260 mV and 420 mV for the oxygen evolution reaction (OER) at 100 mA cm −2 and 1000 mA cm −2 . Moreover, the MOF-OH/NF has good stability in 1.0 M KOH electrolyte solution . This study provides a new idea for the design and synthesis of novel composite electrocatalysts .
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION SCIENCE AND TECHNOLOGY
·
2023
·
IF 2.8
Kaibo Hu,Yucheng Liu,Xiaowen Zhou,Fang Gao,Chuanqi Zhang,Tianci Chen,Ke Li,Jiuyang Lin,Xuewei Li
The waste products of NdFeB magnets are an attractive resource for the recovery of rare earth elements (REEs), especially for neodymium [Nd]. Conventional methods employed to remove ferric (Fe[II]) from Nd solutions involve high energy consumption and the extensive use of chemicals, including oxidants and pH regulators, leading to substantial wastewater generation. In this work, an environmentally friendly approach utilizing CaMg(CO3)2 was presented to remove Fe(II) from Nd solution. Under optimized conditions, including a reaction temperature of 70°C, a CO32-/Fe2+ ratio of 1.5/1, a reaction time of 240 min, and an initial concentration of 200 mg/L, the heterogeneous precipitation reaction on the surface of CaMg(CO3)2 exhibited an exceptional Fe(II) removal efficiency of 98.6%, with a negligible loss of Nd (only 0.8%). It was observed that the CaMg(CO3)2 not only provide a suitable alkaline environment for the selective precipitation of Fe(II), but also significantly enrich the concentration of dissolved oxygen at a high temperature. In fact, at a CaMg(CO3)2 concentration of 2 g/L, the dissolved oxygen concentration in the solution increased significantly to 15.5 mg/L at 70°C. Consequently, the usage of CaMg(CO3)2 facilitated the rapid conversion of Fe(II) to Fe(III) without the need for additional oxidants, which was perfect for the removal of Fe(II) rather than Nd.
研究领域:
环境科学
·
化学工程
·
稀土回收
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF PHYSICS D-APPLIED PHYSICS
·
2022
·Vol. 55
·期 42
·424005
·
IF 3.409
Chang Wang,Ran Duan,Xingcheng Xiao,Yingwei Wang,Zhihui Chen,Yejun Li,Si Xiao,Jun He
Long hexagonal Co3(PO4)2·4H2O nanosheets were synthesized using a hydrothermal method, where their nonlinearity was probed via a femtosecond Z-scan system. The results show that the Co3(PO4)2·4H2O nanosheets exhibit saturable absorption when the incident photon energy is greater than the forbidden band width, while optical limiting is found when the incident photon energy is smaller than the forbidden band width. In particular, the obtained Co3(PO4)2·4H2O nanosheets demonstrate the best optical limiting properties at 600 nm. The present study suggests the cobalt phosphates nanosheets as a promising candidate for optical limiters.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）