CRYSTENGCOMM
·
2013
·Vol. 15
·期 19
·3919-3924
·
IF 3.879
Suli Wu,Yanhui Ning,Jie Chang,Wenbin Niu,Shufen Zhang
Oleic acid together with sodium hydroxide (NaOH) was widely used to control the size, phase and morphology of NaYF4 UCNCs. However, reports are scarce about the modulation of the luminescence intensity and color output of NaYF4 UCNCs by using different amounts of NaOH. Here, we synthesized NaYF4:Yb3+, Er3+ nanocrystals by a hydro/solvent thermal method using oleic acid as ligand with different amounts of NaOH and systematically investigated their upconverted fluorescence spectra. The results indicated that the emission intensity of NaYF4 : Yb3+,Er3+, especially the green emission at 540 nm was dramatically increased as NaOH decreased. The enhancement factors of 540 nm emissions were 48, 42 and 32 for samples prepared with 0 g, 0.2 g and 0.4 g NaOH (the corresponding pH of the reaction solution were 5.9, 6.9 and 7.4), respectively, compared with that of the product prepared with the usually used 0.7 g NaOH (the corresponding pH was 8.3). Importantly, the ratio of green to red (RGR) increased from 0.4 to 5.9 when the pH decreased from 8.3 to 5.9. That is to say, the color output was tuned from orange yellow to nearly pure green. This resulted from the high energy vibration of OH−, which led to nonradiative relaxation from green emission levels (2H11/2 and 4S3/2) to the red emission level (4F9/2) and nonradiative relaxation from the red emission level (4F9/2) to the no emission level (4I11/2) of Er3+.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2020
·Vol. 45
·期 1
·358-364
·
IF 3.288
Yin-chuan Wang,Zi-chen Wang,Gui-yong Xiao,Wei-li Xu,Kai Wang,Yan Jiao,Mei-li Qi,Yu-peng Lu
An oleic acid-assisted solvothermal method has been utilized to prepare hydroxyapatite (HA) nanofibers with a high flexibility and aspect ratio. Understanding the role of oleic acid in the synthesis of HA may provide effective routes for the design of advanced biomaterials. The concentration of OH− ions ([OH−]) has a great impact on the reaction system, which in turn affects the nucleation and crystal growth of HA. In this work, the effect of oleic acid on the morphology and structure of the as-prepared products under different concentrations of NaOH was investigated by XRD, FTIR and FE-SEM. The formation process of HA was also explored to better explain the role of oleic acid based on structured characteristics and morphology evolution. These results showed that oleic acid molecules absorbed on the surface of HA would effectively induce a one-dimensional crystal growth, even if the crystal growth habit had been changed under different [OH−]. For [OH−] < 1.50 M, [OH−]-responsive oleic acid and its corresponding behavior as a pH buffer can regulate pH at a relatively constant value. Besides, the flexible ultralong HA nanofibers can be formed at [OH−] = 1.25–1.50 M, while the crystallite size and preferred growth along the c-axis were both improved with an increase in [OH−] added.
研究领域:
材料科学
·
生物医学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
·
2015
·Vol. 78
·期 2
·293-298
·
IF 1.532
Cui Hongtao,Ma Wenle,Wang Li,Xue Junying
Abstract
In this work, α-Co(OH) 2 monolayer nanosheets were prepared by an intercalation agent-free route utilizing a precipitation reaction between epoxide and aqueous complexes of cobalt ions ([Co(H 2 O) 6 ] 2+ ). The protonation and the following ring-opening reaction of epoxide promoted the hydrolysis of [Co(H 2 O) 6 ] 2+ , leading to the formation of α-Co(OH) 2 nanosheets. The obtained nanosheets were then exfoliated to monolayer nanosheets in formamide under ultrasonic vibration. A possible exfoliation mechanism is proposed for the exfoliating process of α-Co(OH) 2 nanosheets. The water molecules incorporated in the layered structure of α-Co(OH) 2 are considered to be the key medium for the layer exfoliation. It seems that the water molecules coordinated with the cobalt ions weakened the interlayer interaction. Therefore, the extraction of water molecules by formamide readily broke the interlayer connection in α-Co(OH) 2 , resulting in the exfoliation of nanosheets. Graphical Abstract α-Co(OH) 2 monolayer nanosheets were prepared by an intercalation agent-free route utilizing a precipitation reaction between epoxide and aqueous complexes of cobalt ions ([Co(H 2 O) 6 ] 2+ ).
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2023
·
IF 6.6
Chunyan Fan,Zehao Zang,Xiang Li,Junfang Zhang,Ping Yang,Lanlan Li,Xiaofei Yu,Xiaojing Yang,Zunming Lu,Xinghua Zhang
Transition metal hydroxides have superior oxygen evolution reaction (OER) activity but poor hydrogen evolution reaction (HER) performance, which greatly limits the water splitting for hydrogen production. Herein, copper modification of sulfur doped Co(OH) 2 hybrid catalyst (Cu@S-Co(OH) 2 ) was prepared by one-step of electrodeposition method which can serve as efficient hydrogen evolution reaction catalyst. In the presence of sulfur and copper, Cu@S-Co(OH) 2 hybrid catalyst exhibits the best catalytic activity, showing ultralow overpotential of 42 mV at a current density of 10 mA cm −2 . Compared with Co(OH) 2 , the overpotential is improved by nearly 100 mV as well as enhanced stability. In addition, the active site poison experiments proved that the active center is cobalt metal. Combined with the adsorption strength of the catalyst for OH and H species, it is considered that both S and Cu can enhance the adsorption of OH for Co(OH) 2 , while S is contributed to the adsorption of H, and Cu can promote the desorption of H. This work provides a facile method and new insight to enhance the HER activity for transitional metal hydroxides via metal and non-metallic elements co-modulation.
研究领域:
材料科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Nano Materials
·
2020
·
IF 0
Ebrahim Ataeivarjovi,Yubing Liu,Zhigang Tang,Hao Ding,Dong Guo,Xiaofei Song,Guoxun Ben,Mengyue Zhou
The desorption process of CO2 absorbed by the hot-potash-alkali method was studied in this paper. In a traditional hot-potash-alkali process, the temperatures of KHCO3 aqueous solutions are high, moisture vaporization is serious, and energy consumption is high. We proposed that membrane desorption can be used instead of heating desorption and conducted relevant research. PDMS-PTFE-PVDF/PET was used as a composite membrane. The water evaporation considerably declined, and the decomposition conversion rate reduced to 25.5% as the equilibrium liquid-phase concentration decreased. Results show that the PDMS-PTFE-PVDF/PET composite membrane loaded with 1 wt % TiO(OH)2 nanoparticles can be used for membrane desorption, while the decomposition conversion rate of the KHCO3 aqueous solution decreased by only 4.2% after 10 cycles, and the effect was considerably improved. The comprehensive capture energy consumption was about 65% lower than that of the absorption-heating desorption process on account of the positive effect of TiO(OH)2 nanoparticles. Brief calculation, which is based on CO2 concentration tested by a gas analyzer and the linear fitting of the Arrhenius equation, demonstrates that the reaction activation energy can be reduced (Supporting Information).
研究领域:
环境科学
·
材料科学
·
化学工程
✓ 已验证
DOI
MICROCHIMICA ACTA
·
2024
·Vol. 191
·期 7
·1-11
·
IF 5.3
Zhao Zhihua,Yao Longqi,Zhang Shuaiwen,Shi Qingsheng,Rahmatullah Abu Bakker Md,Wu Lan
Industrialization and agricultural demand have both improved human life and led to environmental contamination. Especially the discharge of a lot of poisonous and harmful gases, including ammonia, ammonia pollution has become a pressing problem. High concentrations of ammonia can pose significant threats to both the environment and human health. Therefore, accurate monitoring and detection of ammonia gas are crucial. To address this challenge, we have developed an ammonia gas sensor using In(OH) 3 /Ti 3 C 2 T x nanocomposites through an in-situ electrostatic self-assembly process. This sensor was thoroughly characterized using advanced techniques like XRD, XPS, BET, and TEM. In our tests, the I/M-2 sensor exhibited remarkable performance, achieving a 16.8% response to 100 ppm NH 3 at room temperature, which is a 3.5-fold improvement over the pure Ti 3 C 2 T x MXene sensor. Moreover, it provides swift response time (20 s), high response to low NH 3 concentrations (≤ 10 ppm), and excellent long-term stability (30 days). These exceptional characteristics indicate the immense potential of our In(OH) 3 /Ti 3 C 2 T x gas sensor in ammonia detection. Graphical Abstract
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
CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Man Zhao,Liwu Qiang,Meng Bai,He Xiao,Li Zhang,Junming Zhang,Tianjun Hu,Baoliang Lv,Shengxiang Wang,Jianfeng Jia
Rational design of Ni-based electrocatalysts for methanol electrooxidation reaction (MOR) and in-depth understanding of their catalytic mechanism remain a challenge. Herein, carbon dots/graphene heterostructure is constructed to load Ni(OH) 2 and the role of carbon dots focuses on regulating distribution and electronic property of Ni(OH) 2 . Regulation mechanism of carbon dots on Ni(OH) 2 for optimizing MOR activity are revealed by in-situ Raman, in-situ FTIR, operando electrochemical impedance spectroscopy, X-ray absorption fine structure (XAFS) spectroscopy, and so on. It’s found carbon dots could disperse Ni species and regulate their distribution configuration. Appropriate amount of carbon dots promotes the formation of highly dispersed CDs&Ni(OH) 2 type. Because of strong interaction between Ni(OH) 2 and CDs, coordination environment and local electronic structure of Ni in Ni-CDs/G can be regulated by carbon dots, leading to phase-ratio variation of α-Ni(OH) 2 /β‑Ni(OH) 2 and d-band center shift of Ni(OH) 2 . For the best Ni-4CDs/G electrocatalyst, more formed α-Ni(OH) 2 lead to d-band center downshift from the E F level and optimized its adsorption of methanol. Ni-4CDs/G shows the specific activity of 299.2 mA cm −2 and mass activity of 3756.5 mA mg −1 at peak current. In water splitting test, lower initial overpotential of 140 mV is found in methanol electrolysis than that in water electrolysis. This opens a new door to regulate the metal-based electrocatalysts by CDs and will inspire more people to explore CDs-based materials for electrocatalytic application.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2020
·
IF 4.3
Yi Cheng,Jilin Zhang
Excessive phosphate in wastewater can cause eutrophication of water body, which will worsen the ecological environment and threaten human health and biological life safety. Adsorption of phosphate is the most effective way to remove phosphate, and efficient adsorbent is the key. Amorphous La(OH) 3 has been deemed as a potential phosphate adsorbent on account of high adsorption capacity and environmentally friendly property. However, it also shows some disadvantages such as easy agglomeration, poor water dispersion. In this study, UiO-66-NH 2 was used as carrier to load amorphous lanthanum hydroxide as an adsorbent for phosphate removal. The adsorbent (UiO-66-NH 2 @La(OH) 3 , ULCs) has good water dispersibility and it is easy to be separated and recovered. At the same time, the maximum phosphate adsorption capacity can reach 140.7 mg P/g. The adsorption process accords with pseudo second order kinetic model and Freundlich isotherm model. The thermodynamic results showed that the adsorption process was spontaneous and endothermic. In addition, in the presence of coexisting anions (such as Cl − , SO 4 2− , NO 3 − ), it also exhibited high selectivity and phosphate removal efficiency. Meanwhile, the adsorption capacity keeps at a high level in the range of pH 3–11. By the merit of above-mentioned properties, the prepared material is expected to be an ideal candidate for phosphate removal from contaminated water.
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
JOURNAL OF APPLIED ELECTROCHEMISTRY
·
2020
·Vol. 50
·期 11
·1091-1099
·
IF 2.384
Fa Dejuan,Miao Yuqing
Abstract The NiHPO 4 –Ni(OH) 2 nanowire-assembled bouquets were easily synthesized. Scanning electron microscopy and transmission electron microscopy show the NiHPO 4 –Ni(OH) 2 bouquets form through the organization of nanowires which arrange with certain direction. The electrocatalytic activities of NiHPO 4 –Ni(OH) 2 –GCE towards the oxidation of methanol and urea were studied in NaOH. The nanowire-assembled bouquets were modified on the surface of the glassy carbon electrode, leading to the increase on the surface area of the electrode, which in turn enhanced the current density and electrocatalytic performance for the oxidation of methanol and urea. It shows the potential applications for the utilization of these energy molecules. Graphic abstract
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
ATMOSPHERIC ENVIRONMENT
·
2020
·
IF 4.039
Fenghua Li,Shanshan Tang,Narcisse T. Tsona,Lin Du
Kinetics and mechanism of α-terpineol oxidation by OH radicals were studied in the aqueous phase under acidic condition, and the optical properties of the reaction products were examined. Using the relative rate method, the rate constant of α-terpineol reaction with OH radicals was determined to be (1.3 ± 0.3) × 10 10 M −1 s −1 . The reaction products were analyzed by gas chromatography-mass spectrometry (GC-MS) and the reaction mechanism was proposed. The absorbance changes of the products were monitored by a UV–vis spectrophotometer, and α,β-unsaturated ketone compounds were observed. A certain distribution of α-terpineol in the aqueous phase has the potential to be conducive to the formation of aqueous secondary organic aerosols. At the same time, in order to investigate the persistence of α-terpineol in the atmosphere, its lifetime towards reaction with OH in atmospheric water was determined to be 6.2 h and 1.0 h in urban and remote area, respectively.
研究领域:
大气化学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Wenhui Fang,Tingting Tang,Min Li,Shixian Xin,Ying Wu,Yutao Cao,Zhize Yu,Wei Cui,Zengxi Li,Hong Zhao
Designing catalysts at atomic level fine-tune the electronic structure of surface-active site for efficient water splitting, is a highly desirable approach but also poses significant challenges. This study focuses on the synthesis of a series of electronically tunable metal single-atom (M−SAs) catalysts: M 9 @S-Ni(OH) 2 (M=Pt, Mn, Fe or Cu). Experimental results reveal that introduction of trace S-heteroatoms and metal atoms into Ni(OH) 2 lattice can effectively modulate the electronic structure of M 9 @S-Ni(OH) 2 through modulation of p-d and d-d orbital hybridization, resulting in exceptional performance in water electrolysis. Among M 9 @S-Ni(OH) 2 , Pt 9 @S-Ni(OH) 2 and Fe 9 @S-Ni(OH) 2 exhibit excellent hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) performance, respectively, the overpotential requiring only 7 mV and 269 mV, respectively, at current density of 10 mA cm −2 . (−) Pt 9 @S-Ni(OH) 2 ||Fe 9 @S-Ni(OH) 2 (+) presents a high current density of 531.07 mA cm −2 at cell-voltage of 1.80 V in overall-water splitting (OWS), which is 14.07 times higher than that of the commercial (−) Pt/C||IrO 2 (+) (37.86 mA cm −2 ) system. This work achieves the development of cost-effective and stable electrocatalysts, offering a solution for large-scale and sustainable water-hydrogen conversion.
研究领域:
催化
·
材料科学
·
电化学
·
可再生能源
✓ 已验证
产品关联
DOI
高影响因子
Materials Today Communications
·
2025
·
IF 4.5
Jiahua Cheng,Linya Fei,Xiaoqing Zhou,Beibei Lu,Zhihui Zhang,Le Chen,Guojian Ji
UiO-66 and its functionalized derivatives (UiO-66-X, X = -OH, -NO 2 , -NH 2 ) were successfully synthesized via a solvothermal method, and their structural integrity and functionalization were confirmed. Hydrogen adsorption experiments and Grand Canonical Monte Carlo (GCMC) simulations demonstrated that UiO-66-OH exhibited the highest hydrogen adsorption capacity. At 300 K and 1 bar, its experimental adsorption capacity reached 0.0301 wt%, representing increases of 29.18 %, 3.44 %, and 19.92 % compared to UiO-66, UiO-66-NH 2 , and UiO-66-NO 2 , respectively. At 77 K and 20 bar, its simulated adsorption capacity reached 2.352 wt%, surpassing UiO-66-NH 2 (2.229 wt%) and UiO-66-NO 2 (1.927 wt%). This superior performance is attributed to optimized pore structure and enhanced functional group interactions, providing new insights for optimizing hydrogen storage in UiO-66 materials.
研究领域:
材料科学
·
化学工程
✓ 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）