JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
·
2019
·Vol. 92
·期 1
·200-207
·
IF 1.986
Tang Haodong,Zou Chaoyu,Hu Tao,Zhou Nan,Li Yuzhen,Li Lichun,Han Wenfeng,Li Ying
High surface area Cr 3+ -doped MgF 2 catalysts were synthesized from an aqueous sol–gel method under mild conditions. The amount of Cr 3+ doped in the investigated CrF 3 /MgF 2 catalysts covered a wide range of mole concentration ranging from 0 to 25 mol% to reveal its effect on the properties of the catalysts. The physio-chemical properties of the CrF 3 /MgF 2 catalyst were examined by means of N 2 gas sorption, X-ray powder diffraction (XRD), energy dispersive spectrometer (EDS), and temperature-programmed desorption (TPD) of NH 3 . XRD analysis indicates that the doping of Cr 3+ resulted in reduced crystallinity but did not change the original crystalline structure of MgF 2 . Doping of Cr 3+ (8–25 mol%), on the other hand, can increase the surface area of CrF 3 /MgF 2 significantly to ~300 m 2 /g from ~50 m 2 /g of the nondoped MgF 2 . There is also significant amount of Lewis acid sites formed upon incorporation of Cr 3+ into MgF 2 lattice, which was evidenced from the NH 3 -TPD results. The catalytic activity of the 25 mol% Cr 3+ -doped MgF 2 catalyst on the dehydrofluorination reaction of 1,1-difluoroethane (HFC-152a, CH 3 CHF 2 ) has reached a conversion rate of ~57%, which is over two times higher than the undoped MgF 2 catalyst. Furthermore, the 25 mol% Cr 3+ -doped MgF 2 catalyst has been successfully tested over 210 h upon the dehydrofluorination of CH 3 CHF 2 at 300 °C with the conversion rate remain greater than ~45%.
研究领域:
材料科学
·
催化化学
✓ 已验证
DOI
高影响因子
Nanoscale
·
2021
·Vol. 13
·期 18
·8514-8523
·
IF 7.79
Xiaodan Huang,Xiaojun Wei,Yan Zeng,Lihong Jing,Haoran Ning,Xiaodan Sun,Yingying Li,Di Li,Yuanping Yi,Mingyuan Gao
Spinel oxide nanocrystals are appealing hosts for Cr3+ for forming persistent luminescent nanomaterials due to their suitable fundamental bandgaps. Benefiting from their antisite defect-tolerant nature, zinc gallate doped with Cr3+ ions has become the most studied near-infrared (NIR) persistent luminescent material. However, it remains challenging to achieve persistent luminescence from its inexpensive analogs, e.g., zinc aluminate (ZnAl2O4). Because the radius difference of the cations in the latter system is bigger, it is intrinsically unfavorable for ZnAl2O4 to form Zn–Al antisite defects under mild conditions. Herein, we report a wet-chemical synthetic route for preparing Cr3+-doped ZnAl2O4 nanoparticles with long NIR persistent luminescence. It was demonstrated that methanol (MeOH) as an important component of the mixed solvent played a critical role in tailoring the morphology of the resulting ZnAl2O4:Cr nanocrystals. It could particularly drive the formation of antisite defects in the resulting coral-like nanoparticles bearing zinc-rich cores and zinc gradient peripheries. To disclose the effects of MeOH on the formation of antisite defects as well as particle morphologies, small molecules released during the pyrolysis of metal acetylacetonate precursors were analyzed by using gas chromatography-mass spectrometry. In combination with density functional theory (DFT) calculations, it was found that MeOH can effectively catalyze the thermolysis of metal acetylacetonate precursors, in particular Zn(acac)2. Therefore, MeOH exhibits remarkable effects on the formation of antisite defects by balancing the decomposition rates of Zn(acac)2 and Al(acac)3 through its volume fraction in the reaction system. This work thus constitutes a hitherto less common strategy for achieving NIR persistent luminescence from Cr3+-doped ZnAl2O4 nanoparticles by engineering the cation defects under mild conditions.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
ACS Applied Nano Materials
·
2024
·
IF 5.3
Jianshuai Mu,Aizhu Peng,Xinran Wang,Jin Wang,Zengjiao Hong,Danna Guo,Shulai Lei,Jiajun Wang,En-Cui Yang
Designing low-cost and environmentally friendly oxygen evolution reaction (OER) electrocatalysts to enhance the electrocatalytic water decomposition to produce hydrogen still faces great challenges. In this work, a feasible strategy for metallic/nonmetallic elements co-doping to boost the OER catalytic properties of iron oxyhydroxide is proposed. A series of S and Cr co-doped iron oxyhydroxides nanoarrays loaded on nickel foam (Sx,Cr-FeOOH/NF) were prepared by an electrodeposition–hydrothermal method. The optimized S0.1,Cr-FeOOH/NF exhibits a superior electrocatalytic OER performance with low overpotential (235 mV at 100 mA cm–2), highly outperforming commercial RuO2. Meanwhile, the overpotential of S0.1,Cr-FeOOH/NF increases by only 4 mV after 70 h of stability testing at 100 mA cm–2, demonstrating its durability. The nanoarray with ultrathin nanosheets of S0.1,Cr-FeOOH/NF regulated by S and Cr co-doping can offer abundant active sites and also facilitate mass transportation. The density functional theory (DFT) calculation results show that S and Cr co-doping modifies the electronic structure of S0.1,Cr-FeOOH/NF, which thus optimizes the adsorption energy toward the OER intermediates, promotes the transformation of *O to *OOH (rate-determining step), and thus accelerates the OER kinetics.
研究领域:
材料科学
·
能源化学
✓ 已验证
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2025
·
IF 7.2
Fengxin Cao,Qiaoling Li,Boya Shan,Zhiwei Qi,Chenyu Zhang,Chengcheng Yu
To create an economical, stable, along highly efficient catalyst for the hydrogen evolution reaction, this paper reports on a Cr-doped self-supported Co-P-Cr/NF high-performance HER catalyst synthesized in one step. It exhibits overpotentials of 41.44 mV at −10 mA cm −2 . Moreover, the impedance is only 0.56 Ω, and the double-layer capacitance value is 40.02 mF cm −2 . After a 12-hour stability test, the catalyst shows only minimal overpotential increase. Using techniques including XRD, XPS, SEM, and TEM, the structure of the electrocatalyst was thoroughly investigated. The introduction of Cr and the excellent electronegativity of P enhance the redox capability and show superior intrinsic electrocatalytic ability in Co-P-Cr/NF catalysts. Therefore, the Co-P-Cr/NF catalyst that has been developed shows promise in replacing costly Pt-based electrocatalysts in the HER.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
Frontiers in Materials
·
2019
·
IF 2.689
Xie Lijuan,Li Zhong,Sun Linchao,Dong Baoxia,Fatima Qawareer,Wang Zhe,Yao Zhengjun,Haidry Azhar Ali
Titanium dioxide is considered as one of the potential candidates for high-temperature gas sensing applications due to its excellent sensitivity and stability. However, its practical use as a gas sensor under elevated conditions is limited on account of its selectivity and insufficient understanding of response conversion from n- to p-type. To this context, the present work is intended to prepare and understand the p-type response of anatase TiO2 toward H2 gas (20–1,000 ppm) at elevated temperature (500°C). Sol-gel route is adopted to facilely synthesize powders containing pure and chromium (1–10 at.%) doped TiO2 nanoparticles, which are then brushed onto substrates with already patterned inter-digitated platinum electrodes. In this work, even, the undoped TiO2 samples showed p-type gas sensing response, which then decreased with Cr doping. However, in comparison to previously reported work, the sensing characteristics of all sensors is improved. For instance, 5 at.% Cr-TiO2 showed high response (147), fast response and recovery (142/123s) time, and good selectivity to hydrogen against monoxide and methane. Despite better response values, the TiO2 based samples show instability and drift in baseline resistance; such issues were not observed for Cr-doped TiO2 samples (≥3 at.%). The powders were further analyzed by XRD, SEM, TEM, and XPS to understand the basic characteristics, p-type response and stability. Further, a plausible sensing mechanism is discussed on basis of results obtained from aforementioned techniques.
研究领域:
材料科学
·
气体传感器技术
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2021
·
IF 9.229
Li Yang,Hao Wu,Liang Zhang,Gaojie Zhang,Hongda Li,Wen Jin,Wenfeng Zhang,Haixin Chang
The intrinsically nonmagnetic feature of van der Waals (vdW) layered transition-metal dichalcogenide (TMDC) semiconductors limits the spintronic applications of these semiconductors. In this paper, we demonstrate a facile Te flux strategy to induce intrinsic ferromagnetism in the vdW layered 2H-MoTe2 semiconductor by magnetic chromium (Cr) doping. The Curie temperature (Tc) and saturation magnetization (Ms) can be well tuned by adjusting the Cr doping concentration. A notable Tc up to 275 K can be achieved for the vdW layered Cr-doped 2H-MoTe2 bulk crystals, which is much higher than that of recently reported van der Waals ferromagnetic semiconductors (Tc is mostly less than 70 K), in contrast to the diamagnetic feature of the pristine MoTe2. Meanwhile, the highest Ms of the vdW layered Cr-doped 2H-MoTe2 bulk crystals can reach 4.78 emu g–1, which is stronger than most values reported for magnetic-element-doped van der Waals materials. In addition, all of the as-grown semiconducting Cr-doped 2H-MoTe2 (Cr-2H-MoTe2) single crystals display a large magnetic anisotropy with an out-of-plane easy axis of magnetization. The observed ferromagnetism in the Cr-2H-MoTe2 has intrinsic characteristics, which can be mainly attributed to the spin polarization caused by Cr doping as confirmed by the density functional theory (DFT) calculations. Our approach offers an avenue to tune the ferromagnetism in the vdW layered semiconductor and explore its diverse spintronic and magnetoelectric applications.
研究领域:
材料科学
·
凝聚态物理
·
自旋电子学
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2021
·
IF 3.764
Wuyuan Liu,Zihan Gao,Xiangyun Zhao,Jiajian Gao,Runnong Yang,Lin Yu
The Cr-doped CeO2–TiO2 catalysts (CrCeTi) were produced via a coprecipitation method and used for selective catalytic reduction (SCR). The CrCeTi catalyst has good catalytic performance and sulfur resistance. The results of X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), NH3-TPD, NO-TPD, X-ray photoelectron spectroscopy (XPS), and H2 temperature-programmed reduction (H2-TPR) suggested that the CrCeTi catalyst with high specific surface area (SSA), strong surface acidity, enhanced redox properties, and effective electron transfer (3Ce4+ + Cr3+ ↔ 3Ce3+ + Cr6+) were the important promotion factors for excellent SCR properties. The in situ diffuse reflectance infrared spectroscopy (DRIFTS) indicated that the incorporation of Cr could improve the adsorption capacity of nitrate and the activation capacity of NH3, which were conducive to enhancing the catalytic activity. The thermogravimetric analysis-mass spectrometry (TG-MS) confirmed that the doping of Cr reduced SO2 surface adsorption and promoted the decomposition of NH4HSO4 (ABS). Therefore, the CrCeTi catalyst showed excellent resistance to SO2 poisoning.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2024
·
IF 6.7
Fanjia Sun,Xueqing Tian,Jianbing Zang,Rui Zhu,Zhiwei Hou,Youbin Zheng,Yanhui Wang,Liang Dong
Transition metal sulfides, recognized for their platinum-like activity, were prominent in electrolytic water hydrogen production research. In this context, we reported a NiS/NiS 2 heterostructure composite active center electrocatalyst optimized by Cr doping (Cr-NiS/NiS 2 @NF) based on the dual regulation of defect engineering and interface engineering. The electronic structure of Ni and S could be adjusted by Cr doping, and the creation of defects exposed more active sites. Meanwhile, the resulting NiS/NiS 2 heterogeneous interface acted as a composite activity center, enhancing the alkaline HER process rate. The Cr-NiS/NiS 2 @NF achieved 100 mA cm −2 at an overpotential of 172.8 mV. Density functional theory analysis confirms the significant decrease in the water dissociation potential barrier, attributable to the electron redistribution caused by Cr doping. The optimized heterointerface functioned as a composite activity center. Here, the Cr-NiS component effectively facilitated water dissociation, while the NiS 2 component primarily enhanced H 2 generation and desorption. The introduction of Cr significantly improved the electronic coupling at the bi-phase interfaces, thereby accelerating the transport of hydrogen intermediates. This study revealed the modulation of electron distribution at the Cr-doped nickel sulfide heterointerface, offering deep atomic-scale insights. These findings provide novel perspectives for the field of hydrogen production via water electrolysis.
研究领域:
材料科学
·
催化化学
·
能源研究
✓ 已验证
产品关联
DOI
高影响因子
Surfaces and Interfaces
·
2025
·
IF 6.3
Jun Hua,Xianwen Wu,Fangxi Xie,Mingmei Wu
Manganese-based aqueous zinc-ion batteries are considered to be one of the most promising candidates owing to its abundant resources, environmental friendliness and high safety. However, some severe problems associated with cathode are mainly plagued by Mn (III) disproportionation and Jahn-Teller distortion, leading to undesired manganese dissolution and reduced their cycle life. Herein, Cr-doped δ-MnO 2 is synthesized by a simple hydrothermal method. This study demonstrates how Cr-doping addresses these challenges by narrowing the lattice spacing between MnO 2 layers, promoting self-confinement, and mitigating Mn 2+ dissolution. As a result, Cr-doped δ-MnO 2 exhibits enhanced crystal structure stability, with superior capacity retention of 65.80 % compared to 51.53 % for pristine δ-MnO 2 after 300 cycles at 500 mA/g. Our findings provide an alternative avenue for mitigating Mn dissolution, laying the groundwork for the adoption of Zn/MnO 2 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
·
2022
·
IF 7.392
Xinyu Zheng,Shichao Sun,Yu Liu,Di Li,Dan Tian,Jianjun Zhu,Deli Jiang
Designing high-efficiency bifunctional catalysts for alkaline water splitting is well anticipated, but is a considerable challenge owing to sluggish kinetics of hydrogen/oxygen evolution reaction (HER/OER). Herein, chromium and nitrogen co-doped nickel selenide nanosheet arrays supported on nickel foam (Cr–NiSe 2 –N/NF) are rationally devised as an effective bifunctional electrocatalyst through an anion and cation dual-doping approach for overall water splitting. The as-obtained electrocatalysts displayed eminent catalytic performance for both OER (η 10 = 222 mV, η 50 = 310 mV) and HER (η 10 = 123 mV, η 100 = 256 mV) in 1 M KOH resolution. Furthermore, the Cr–NiSe 2 –N/NF as a bifunctional electrocatalyst only requires 1.59 V cell voltages at 10 mA cm −2 and exhibits excellent durability of 50 h. Experimental analyses and density functional theory (DFT) calculations prove that the simultaneous introduction Cr and N into NiSe 2 could synergistically adjust the electronic configuration and upshift the transition metal d-band center, which facilitates the enhancement of the adsorption capabilities towards reaction intermediates of HER and OER, thus enhancing catalytic activities. This work affords an efficient strategy for NiSe 2 -based electrocatalysts to improve electrocatalytic performance and motivates further research to construct highly active bifunctional electrocatalysts.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
CRYSTENGCOMM
·
2022
·Vol. 24
·期 32
·5724-5732
·
IF 3.756
Boyuan Di,Pengzhen Zhang,Hongfei Yin,Peng Han,Hao Wu,Gaojie Zhang,Wen Jin,Xiaokun Wen,Wenfeng Zhang,Haixin Chang
The discovery of two-dimensional (2D) van der Waals (vdW) ferromagnets has provided a broad platform for the study of spintronics and many novel physical phenomena. However, vdW ferromagnetic crystals generally have a low Curie temperature and poor air stability and their magnetic properties are difficult to modulate. As a layered Dirac semimetal, NiTe2 has excellent properties such as high electrical conductivity and high air stability. In this work, we report for the first time the introduction of ferromagnetism into NiTe2 single crystals by doping Cr atoms with the Te-flux method. By controlling the Cr content, the Curie temperature can be tuned from 210 K to 248 K and the saturation magnetic moment from 1.54 emu g−1 to 2.27 emu g−1 which is much higher than the defective magnetism caused by doping. The doped nanosheets still have extremely high air stability, in contrast with most vdW 2D ferromagnet crystals. The results provide opportunities for the study of new highly-tunable, air-stable vdW ferromagnets and their potential applications.
研究领域:
凝聚态物理
·
材料科学
·
自旋电子学
·
二维材料
·
磁性材料
✓ 已验证
DOI
高影响因子
Journal of Energy Storage
·
2025
·
IF 9.8
Xiaohong Chen,Xuezhen Zhai,Yongqi Wu,Xuzhe Wang,Lamei Zhang,Cui Shang,Huawei Zhang,Chengzhou Zhao,Jimin Shang,Dewei Liu
Vanadium-based oxides have gained significant attention as promising cathode materials for aqueous zinc-ion batteries, owing to their high theoretical capacities, the ability to undergo multi-electron transfer, and varied crystal structures. Despite these advantages, challenges related to structural instability and poor electrical conductivity remain significant barriers to their practical application. In this study, Cr-doped VO 2 (B) nanorods were prepared using a hydrothermal treatment process as a promising candidate for aqueous zinc-ion battery cathodes. The multivalent nature of vanadium promotes a variety of redox reactions, resulting in high specific capacities. Chromium ion doping increases oxygen vacancy defects and provides efficient channels for electron transfer. The nanorod morphology offers an increased specific surface area, thereby promoting a higher density of active sites. Positron annihilation lifetime spectroscopy indicates that the generated defects exist in the form of single vacancies. Thanks to the unique tunnel structure and micro-morphology advantages, the CrVO cathode exhibits rapid electron transfer and superior reaction kinetics. Electrochemical performance is optimized at a chromium ion doping concentration of 6 at.%, achieving a high specific capacity of 312.8 mAh g −1 at 0.1 A g −1 and retaining 188.3 mAh g −1 at 5 A g −1 after 2000 cycles, with a remarkable capacity retention of 90.39 %, indicating exceptional long-term cycling stability. This work optimizes the electrochemical performance by introducing different concentrations of chromium ions into the monoclinic VO 2 , thereby altering the Cr 3+ /Cr 6+ and V 4+ /V 5+ ratio, providing a feasible approach for developing high-performance vanadium-based aqueous zinc-ion battery cathodes.
研究领域:
材料科学
·
电化学
✓ 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）