ACS Applied Energy Materials
·
2024
·
IF 5.4
Jiajing Zhu,Hui Wang,Yuqi Zhai,Liangjun Huang,Jie Cui,Liuzhang Ouyang,Min Zhu,Jacques Huot
MgH2 is a promising solid-state hydrogen storage medium with a high hydrogen capacity and low cost, but it suffers from high hydrogen sorption temperatures. In this work, Cr-doped TiO2 solid solution nanocatalysts were synthesized and demonstrated to significantly reduce the hydrogen sorption temperatures and pressure of MgH2. The Ti(5Cr)O2 catalyzed MgH2 releases over 6.1 wt % of H2 at 200 °C, and even at 175 °C, 2.62 wt % H2 can be desorbed. The dehydrogenation activation energy is greatly reduced to 85.3 ± 8.7 kJ/mol, which is ∼49.7 kJ/mol less than that observed for pure MgH2. The dehydrogenated product can absorb 4.5 wt % of H2 within 10 s at a low temperature of −20 °C and back pressure of 30 bar, or the hydrogen uptake content can reach 4.81 wt % under 5 bar and 75 °C. The mechanism study indicates that the Cr-doped TiO2 can markedly reduce the adsorption energy and dissociation energy barrier of H2 molecules and greatly enhance the dissociation ability of H on the catalyst surface. This work demonstrates the potential of modified TiO2 as a cost-effective and efficient catalyst for Mg-based hydrogen storage materials.
研究领域:
材料科学
·
能源存储
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE ENERGY INSTITUTE
·
2022
·
IF 6.47
Longyi Xue,Ninghan Wei,Cheng Zhao,Xiaomei Hu,Junge Yun,Zimo Chen,Zhiyi Deng,Zhihang Chen
CeO 2 as selective catalytic reduction (SCR) catalyst has attracted wide attention due to its abundant surface acidity and excellent oxygen storage/release capacity. However, its further implication was hindered owing to insufficient catalytic activity and SO 2 resistance. Novel Cr doped CeO x catalysts were synthesized by solid phase method and used for NH 3 -SCR of NO x at middle-low temperature. The effect of Cr addition on the SCR performance and physicochemical properties of CeO 2 catalyst was investigated by activity test and characterizations. Among the tested catalysts, Cr(0.4)-CeO x catalyst exhibited excellent NO x removal efficiency, with >90% NO conversion within 180–300 °C, 100% NO conversion at 220 °C and outstanding SO 2 resistance at 240 °C under 100 or 600 ppm SO 2 . The characterizations results revealed that Cr modified CrCeO x catalyst could effectively increase BET surface area, pore volume, surface acidity and redox capacity. In situ DRIFTS indicated that SCR reactions over Cr(0.4)-CeO x catalyst followed Eley-Rideal mechanism and active –NH 2 was the major intermediate species. After sulfuration, Cr(0.4)-CeO x still exhibited excellent SCR activity due to the increase of Cr 6+ , Ce 3+ and O α concentration and the formation of Cr–O–Ce bond, new Brønsted acid site and more crystallized Cr 2 O 3 .
研究领域:
催化化学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
Nanomaterials
·
2024
·Vol. 14
·期 10
·848
·
IF 4.4
Jun Wu,Gaofeng Shao,Xiaodong Wu,Sheng Cui,Xiaodong Shen
A novel Cr-doped BaTiO3aerogel was successfully synthesized using a co-gelation technique that involves two metallic alkoxides and a supercritical drying method. This freshly prepared aerogel has a high specific surface area of over 100 m2/g and exhibits improved responsiveness to the simulated sunlight spectrum. Methyl orange (MO) was chosen as the simulated pollutant, and the results reveal that the Cr-doped BaTiO3aerogel, when modified with the noble metal silver (Ag), achieves a pollutant removal rate approximately 3.2 times higher than that of the commercially available P25, reaching up to 92% within 60 min. The excellent photocatalytic performance of the Ag-modified Cr-doped BaTiO3aerogel can be primarily attributed to its extensive specific surface area and three-dimensional porous architecture. Furthermore, the incorporation of Ag nanoparticles effectively suppresses the recombination of photo-generated electrons and holes. Stability and reusability tests have confirmed the reliability of the Ag-modified Cr-doped BaTiO3aerogel. Therefore, this material emerges as a highly promising candidate for the treatment of textile wastewater.
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
Inorganic Chemistry Frontiers
·
2019
·Vol. 6
·期 11
·3057-3062
·
IF 5.934
Weixuan Zeng,Sheng Cao,Lulu Qiao,Anquan Zhu,Quanyin Ma,Xiewen Xu,Yi Chen,Jun Pan
In the present study, we report a one-step hydrothermal synthesis of visible-light response Cr-doped Sr2Ta2O7 nanosheets for photocatalytic hydrogen generation. It is discovered that the Cr ion is successfully doped into the Sr2Ta2O7 nanosheet crystal lattice and uniformly distributed without changing the crystal structure and morphology of the Sr2Ta2O7 host. Compared to pristine Sr2Ta2O7, the as-prepared Cr-doped Sr2Ta2O7 photocatalysts show enhanced photocatalytic activity for hydrogen generation under visible-light irradiation. The spectroscopy and Mott–Schottky results reveal that proper Cr doping can narrow the band gap of Sr2Ta2O7 as well as facilitate the separation of photo-generated electrons and holes, thus enhancing the photocatalytic performance under visible-light irradiation. This work provides a simple approach to fabricate visible-light active tantalum-based oxide photocatalysts.
研究领域:
材料科学
·
能源科学
✓ 已验证
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2017
·
IF 4.798
Xiaoming Lou,Zhihao Xu,Zhibin Luo,Chunfu Lin,Chao Yang,Hua Zhao,Peng Zheng,Jianbao Li,Ning Wang,Yongjun Chen,Hui Wu
The recently explored FeNb 11 O 29 is an advanced anode material for lithium-ion batteries due to its large specific capacity and high safety. However, its poor electronic conductivity significantly limits its rate capability. To tackle this issue, a Cr 3+ doping is employed, and Cr x Fe 1- x Nb 11 O 29 ( x = 0 and 0.2) materials were fabricated using a solid-state reaction. X-ray diffraction analyses combined with Rietveld refinements demonstrate that the Cr 3+ doping does not destroy the orthorhombic shear ReO 3 crystal structure ( Amma space group) of FeNb 11 O 29 or obviously change the unit cell volume. Scanning electron microscopy images combined with specific surface area tests reveal the similar particle size after the Cr 3+ doping. Due to the free 3 d electrons in the Cr 3+ ions, the electronic conductivity of Cr 0.2 Fe 0.8 Nb 11 O 29 is enhanced by three orders of magnitude comparing with FeNb 11 O 29 . Consequently, Cr 0.2 Fe 0.8 Nb 11 O 29 exhibits improved electrochemical properties. At 0.1C, it delivers a large reversible capacity of 254 mAh g −1 . At 10C, it still provides a large capacity of 123 mAh g −1 with large retention of 86.9% after 500 cycles. In contrast, FeNb 11 O 29 shows a small capacity of 57 mAh g −1 and small retention of 41.6%. These results reveal that Cr 0.2 Fe 0.8 Nb 11 O 29 can be a promising anode material for high-performance lithium-ion batteries.
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
·
2017
·
IF 3.387
Hong-Mei Cheng,Shi-Xi Zhao,Xia Wu,Jian-Wei Zhao,Lei Wei,Ce-Wen Nan
The crystal structure of the Li 2 MnSiO 4 cathode material would collapse during the charge and discharge process because of that the Mn-O coordination polyhedron changed from [MnO 4 ] into [MnO 6 ] in the process of Mn +2 to Mn +4 , but the Cr element could remain [CrO 4 ] crystal ligand from Cr +2 to Cr +4 , so Cr element substitution was used to improve the structural stability of the Li 2 MnSiO 4 cathode material. In this work, Li 2 Mn 1-x Cr x SiO 4 /C nanocomposites were synthesized by solid-state method. XRD, SEM and TEM observations show that the as-prepared Li 2 Mn 1-x Cr x SiO 4 /C materials presents an orthorhombic crystal structure (S.G. Pmn2 1 ), the particle size of Li 2 Mn 1-x Cr x SiO 4 /C powder ranges from 50 to 100 nm. The XRD and XPS results indicate that Cr +2 is successfully doped into Li 2 MnSiO 4 lattice and has well compatibility with Li 2 MnSiO 4 . The electrochemical results display that Li 2 Mn 92.5% Cr 7.5% SiO 4 /C exhibits significantly enhanced cycle stability and discharge capability. The initial discharge capacity of the Li 2 Mn 92.5% Cr 7.5% SiO 4 /C sample is 255 mAh g −1 , and the discharge capacity was still about 60 mAh g −1 after 50 cycles. Furthermore, the XRD patterns, TEM images and Raman analysis reveal that the Cr doping enhances the structural stability of Li 2 Mn 1-x Cr x SiO 4 /C and improves the electrochemical activity of the cathode. Thus, the Li 2 Mn 92.5% Cr 7.5% SiO 4 /C have shown potential applications for lithium ion batteries.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
CHEMICAL PHYSICS
·
2019
·
IF 1.822
Tong-Tong Zhang,Xiang-Dong Gao,Yong-Qing Wu,Jing-Nan Yang,Xiao-Min Li
Cr-doped BaSnO 3 (BaSn 1-x Cr x O 3 , BSCO-x, x = 0–0.15) thin films with nanoporous structure were deposited on fluorine-doped tin oxide substrates via a colloidal solution route. The BSCO-x films exhibited single cubic perovskite phase and nanoporous feature, with the typical specific surface area of 18.98 m 2 /g and pore size of 10.75 nm (BSCO-0.15). The lowest band gap of 2.68 eV and a high transparency (above 70% in 500–800 nm) were realized in BSCO-0.15 film. This work paves a way toward perovskites with tunable band gap and nanoporous structures for varied photo and photoelectric devices.
研究领域:
材料科学
·
光电子学
✓ 已验证
产品关联
DOI
高影响因子
Nanoscale
·
2015
·Vol. 7
·期 12
·5395-5402
·
IF 7.394
Shao-jie Li,Da Li,Wei Liu,Zhidong Zhang
Monoclinic Fe3−xCrxSe4 nanostructures (0 ≤ x ≤ 2.5) were synthesized using a high-temperature solution chemical method. With increasing the Cr doping, the peak positions in the X-ray diffraction (XRD) patterns of Fe3−xCrxSe4 nanostructures slightly shifted to lower 2θ values due to the changes in lattice parameters. Expansions in the unit cell volumes of Fe3−xCrxSe4 nanostructures (x > 0.3) may have been responsible for enhancing the ferromagnetic (FM) interaction between magnetic ions, which resulted in a significant increase in the Curie temperature (TC) from 331 K for Fe3Se4 to 429 K for FeCr2Se4, distinctly differing from the magnetic properties of the corresponding bulk materials. A room-temperature coercivity (HC) analysis showed an obvious increase from 3.2 kOe for Fe3Se4 to 12 kOe for Fe2.3Cr0.7Se4 nanostructure, but gradually decreased upon further increasing the Cr content.
研究领域:
材料科学
·
物理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Materials Chemistry A
·
2015
·Vol. 3
·期 12
·6586-6591
·
IF 7.443
Hongfei Shi,Huaqiao Tan,Wan-bin Zhu,Zaicheng Sun,Yuejia Ma,Enbo Wang
A series of Cr-doped Bi4Ti3O12/Bi2Ti2O7 (BTO) heterostructure fibers have been synthesized via a one-step, facile and economical electrospinning/calcination process. SEM and TEM results reveal that the diameters of the as-prepared fibers are 100 ± 30 nm. The light adsorption of Bi4Ti3O12 and Bi2Ti2O7 in the fibers has been remarkably improved by Cr doping. With increased Cr doping, XRD and XPS show that the amount of Bi2Ti2O7 increases in the fibers. As a result, the Bi4Ti3O12/Bi2Ti2O7 heterojunction structure is enhanced, which further promotes the charge separation of photogenerated charge carriers. Photocatalytic tests indicated that the as-prepared Cr-doped Bi4Ti3O12/Bi2Ti2O7 fibers exhibit good photocatalytic activity for photodegradation of methyl orange (MO) under visible-light irradiation.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
Materials
·
2021
·Vol. 14
·期 19
·5598
·
IF 3.623
Huajiang Zhou,Shaozhao Wang,Daowen Wu,Qiang Chen,Yu Chen
In this work, a kind of Gd/Cr codoped Bi3TiNbO9Aurivillius phase ceramic with the formula of Bi2.8Gd0.2TiNbO9+ 0.2 wt% Cr2O3(abbreviated as BGTN−0.2Cr) was prepared by a conventional solid-state reaction route. Microstructures and electrical conduction behaviors of the ceramic were investigated. XRD and SEM detection found that the BGTN−0.2Cr ceramic was crystallized in a pure Bi3TiNbO9phase and composed of plate-like grains. A uniform element distribution involving Bi, Gd, Ti, Nb, Cr, and O was identified in the ceramic by EDS. Because of the frequency dependence of the conductivity between 300 and 650 °C, the electrical conduction mechanisms of the BGTN−0.2Cr ceramic were attributed to the jump of the charge carriers. Based on the correlated barrier hopping (CBH) model, the maximum barrier heightWM, dc conduction activation energyEc, and hopping conduction activation energyEpwere calculated with values of 0.63 eV, 1.09 eV, and 0.73 eV, respectively. Impedance spectrum analysis revealed that the contribution of grains to the conductance increased with rise in temperature; at high temperatures, the conductance behavior of grains deviated from the Debye relaxation model more than that of grain boundaries. Calculation of electrical modulus further suggested that the degree of interaction between charge carriersβtended to grow larger with rising temperature. In view of the approximate relaxation activation energy (~1 eV) calculated fromZ″andM″ peaks, the dielectric relaxation process of the BGTN−0.2Cr ceramic was suggested to be dominated by the thermally activated motion of oxygen vacancies as defect charge carriers. Finally, a high piezoelectricity ofd33= 18 pC/N as well as a high resistivity ofρdc= 1.52 × 105Ω cm at 600 °C provided the BGTN−0.2Cr ceramic with promising applications in the piezoelectric sensors with operating temperature above 600 °C.Keywords:Aurivillius phase ceramic;Bi3TiNbO9;electrical conduction behaviors;impedance spectrum;electrical modulus
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Materials Chemistry A
·
2015
·Vol. 3
·期 7
·3935-3943
·
IF 7.443
Dongfang Hou,Xianluo Hu,Wingkei Ho,Pei Hu,Yunhui Huang
Novel porous Cr-doped SrTiO3 nanotubes were fabricated using a simple and economical electrospinning technique with subsequent calcination. The average outer diameter of the nanotube was approximately 100 nm, and the multimodal porous netlike framework with high specific surface area was favorable for light harvesting and matter diffusion. Photocatalytic activity was evaluated by degradation of azo dye acid orange 7 and removal of NO under visible light irradiation. The enhanced photocatalytic activity of porous Cr-doped SrTiO3 nanotubes was attributed to the one-dimensional tube-like architecture, high specific surface area, multimodal pore size distribution, and proper Cr doping.
研究领域:
材料科学
·
环境科学
·
化学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2021
·Vol. 32
·期 8
·11028-11042
·
IF 2.478
Tang Ping,Cao Ming,Yu Jian,Wang Lifang,Zhang Deqin
Bi 1− x Ba x Fe 1− y Cr y O 3 (BBFCO: x = 0, y = 0; x = 0.05, y = 0; x = 0, y = 0.05; x = 0.05, y = 0.05; x = 0.1, y = 0; x = 0, y = 0.1; x = 0.1, y = 0.1; x = 0.2, y = 0) nanoparticles were prepared by a simple cost effective ethylene glycol-based sol–gel technique. The calcination temperature was set at 600 °C for 120 min with a heating rate of 10 °C/min. Effects of Ba, Cr dopant on structural, optical and magnetic properties of BiFeO 3 (BFO) nanoparticles have been studied. Perovskite structure was confirmed by the metal-oxide absorption bands appeared at 559 cm −1 and 438 cm −1 in Fourier-transform infrared spectroscopy spectra, which are the characteristic bands of FeO 6 octahedral groups in perovskite structure. X-ray diffraction patterns confirmed that Barium (Ba) is an effective dopant to suppress the impurity phases in Cr-doped BFO. Phase transitions from rhombohedral to orthorhombic phase in all doped samples were verified by Rietveld refinement and Raman analysis. Rhombohedral, orthorhombic and tetragonal phases coexist in Bi 0.9 Ba 0.1 FeO 3 and Bi 0.8 Ba 0.2 FeO 3 , which can be ascribed to the serious lattice distortion due to high-level Ba doping. Well-crystalline BBFCO nanoparticles were observed and the particle size distribution of all samples was calculated from transmission electron microscope images. Ba–Cr co-doping resulted in a dramatic reduction in the particle size. Optical absorption spectra indicated that the optical bandgaps of the doped samples are about 2.20 eV. Clear hysteresis loops were observed in all doped BFO, which indicate their ferromagnetic order at room temperature. Gradually enhanced ferromagnetic property was realized in Ba-doped BFO. The magnetization (at 20 kOe) of BFO, BFO-5Ba, BFO-10Ba and BFO-20Ba are 0.24, 0.33, 1.00 and 1.25 emu/g, respectively. The remanent magnetization of them are near zero, 0.08, 0.44 and 0.53 emu/g, respectively. Particular shape of wasp-waist hysteresis loops observed in BFO-5Ba, BFO-5Cr and BFO-5BaCr can be ascribed to the coexistence of different magnetic phases, and the mixture of single domain and superparamagnetic particles.
研究领域:
材料科学
·
物理学
✓ 已验证
DOI
高影响因子
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