Journal of Materials Chemistry A
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2018
·Vol. 6
·期 28
·13668-13675
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IF 9.931
Hongtao Guan,Pan Cai,Xiaomeng Zhang,Yanlin Zhang,Gang Chen,Chengjun Dong
We demonstrate the design and fabrication of novel Cu2O@Mn(OH)2 core–shell hierarchical structures using octahedral Cu2O as a template. The Cu2O backbone supports the growth of an ultrathin Mn(OH)2 nanoflake shell, leading to a relatively large surface area (65.8 m2 g−1) for sufficient utilization of active materials. Cyclic voltammetry (CV) and galvanostatic charge–discharge measurements (GCD), as well as cycling stability and electrochemical impedance spectroscopy (EIS) were performed to examine the electrochemical performances of the Cu2O@Mn(OH)2 core–shell structure. Applied as a supercapacitor electrode, the Cu2O@Mn(OH)2 composite delivers a high specific capacitance of 540.9 F g−1 at 1 A g−1 and an energy density of 6.4–18.2 Wh kg−1. After conducting 3000 cycles at 5.0 A g−1, the capacitance retention of 71.5% was achieved. The unique core–shell structure of the Cu2O@Mn(OH)2 composite favours the effective transport of electrolytes and shortens the ion diffusion path. In addition, the synergetic effects from both Cu2O and Mn(OH)2 significantly enhance the electrochemical performances. Our findings suggest that this Cu2O@Mn(OH)2 core–shell is very promising for next generation high-performance supercapacitors.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2024
·
IF 4.9
Linghui Cao,Yuanxinyi Zhou,Tianyu Shen,Aijuan Xie,Shiping Luo,Baozhu Yang
Dopamine (DA), widely recognized as the most prevalent catecholamine neurotransmitter in the brain, functions as a vital regulator of various physiological processes within the central nervous system. Meanwhile, uric acid (UA) serves as the terminal product of purine metabolism, and hyperuricemia emerges as a significant risk factor for gout, with a steep escalation in risk as blood uric acid levels surge. Consequently, monitoring the concentrations of DA and UA in biological fluids is crucial not only for the treatment of related disorders but also for enhancing disease prevention strategies. In this work, the blooming hydrangea shaped ZnCo(OH)F/carbon dots (CDs) composite was grown on carbon cloth (CC) substrate by a simple hydrothermal method, which was used as a flexible sensor for the detection of DA and UA. The unique open structure and morphologic adjustment strategy of ZnCo(OH)F/CDs/CC provided a large surface area and highly exposed active site. After screening the experimental variables that affect the sensor performance, the optimal ZnCo(OH)F/CDs/CC flexible electrode achieved individual and simultaneous detection for DA and UA in the concentration ranges of 1.0 220.0 µM and 1.0 500.0 µM, the detection limits (LOD) of DA and UA were 0.0129 and 0.044 μM, respectively (S/N=3). In addition, the sensor exhibited good repeatability, stability and selectivity, realizing the detection of DA and UA in human serum with recovery rate of 95.20 % 105.3 %. Also, the density functional theory (DFT) calculations were used to explore the interaction between electrode material and detected substrate. A simple hydrothermal method was utilized to grow the ZnCo(OH)F/CDs composite onto the CC substrate. The presence of F − in ZnCo(OH)F can increase the charge mobility and improve the conductivity. ZnCo(OH)F/CDs/CC as flexible electrode material can determine DA and UA simultaneously in human serum with a satisfactory recovery rate. This flexible sensor has a broad application prospect in the manufacture of wearable devices.
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DALTON TRANSACTIONS
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2025
·
IF 3.3
Hao Yin,Bingxian Wu,Xueyang Leng,Hong Gao,Jing Yao
Electrolytic water-splitting has the advantages of high efficiency, environmental friendliness, and sustainability. It is becoming a leading approach for producing hydrogen. In order to improve the efficiency of water-splitting, a bifunctional electrocatalyst with high performance is needed. Herein, we present a novel approach to construct a bifunctional electrocatalyst for overall water-splitting by compounding Ni(OH)2 and CoP. This combination induced charge optimization, thereby leading to surface reconstruction. The nanocomposite displayed outstanding catalytic performance, benefiting from its more reactive surface area, improved conductivity and enhanced electrocatalytic activity. The resulting Ni(OH)2/CoP electrocatalyst exhibited excellent catalytic performance, with low overpotentials of 266 mV at 50 mA cm−2 for the OER and 71 mV at −10 mA cm−2 for the HER, and required only 1.54 V to reach 10 mA cm−2 in an overall water-splitting device, overtaking most of the recently reported Co- and Ni-based catalysts. This innovative strategy offers new directions for the design of efficient electrocatalysts.
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ELECTROCHIMICA ACTA
·
2016
·
IF 4.803
Zhen Liu,Huajun Zhou,Simon S. Ang,Jian-Jun Zhang
Here we report the evaluation of natrochalcite (Na[Cu 2 (OH)(H 2 O)(SO 4 ) 2 ]), an anionic layered structure [Cu 2 (OH)(H 2 O)(SO 4 ) 2 ] − charge-balanced by Na + , as an anode material for both Li- and Na-ion batteries. It delivers 224 mAh/g and 175 mAh/g in the first discharge in the Li + - and Na + -cells respectively, and decomposes to form amorphous matrixes during this step. In the subsequent charge, the original layered structure is unusually partially recrystallized back from the matrixes, resulting in 53 mAh/g and 35 mAh/g discharge capacities in the second discharge respectively. In subsequent cycling, Li + in the electrolyte is found to replace the original Na + during cycling in the Li + -cell and the electrode in the Li + -cell demonstrates better capacity retention rates than that in the Na + -cell, possibly due to Li + being smaller than Na + and thus decomposition-recrystallization cycles being more reversible during cycling in the Li + -cell.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2016
·
IF 3.205
Jianmin Chen,Qilu Yao,Jia Zhu,Xiangshu Chen,Zhang-Hui Lu
Bimetallic Rh–Ni nanoparticles (NPs) immobilized on the cerium hydroxide carbonate (Ce(OH)CO 3 ) have been successfully prepared by a facile co-reduction route, and characterized by XRD , SEM , TEM , EDX, ICP , XPS , and TG-DTA. The as-synthesized Rh–Ni/Ce(OH)CO 3 nanocomposites (NCs) with different metal compositions were applied as the highly efficient catalysts for hydrogen generation from the alkaline solution of hydrazine (N 2 H 4 ). Especially, the Rh 55 Ni 45 /Ce(OH)CO 3 NCs exerted the highly activity and 100% H 2 selectivity for the decomposition of hydrazine, providing high turnover frequency (TOF) values of 150 h −1 at 30 °C and 395 h −1 at 50 °C, respectively, relative high values for the metal catalysts . The activation energy for the decomposition of hydrazine catalyzed by Rh 55 Ni 45 /Ce(OH)CO 3 NCs was measured to be 38.8 kJ/mol, lower than most of the values reported for this reaction using many different catalysts. This excellent catalytic performance could be attributed to not only the strain and ligand effects between Rh and Ni, but also the strong interaction between RhNi NPs and Ce(OH)CO 3 support. Such a highly catalyst may greatly encourage the practical application of hydrazine as a hydrogen storage material.
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ChemElectroChem
·
2017
·Vol. 4
·期 11
·2826-2834
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IF 4.136
Shuxia Yuan,Chunxiang Lu,Ying Li,Xiaomin Wang
Graphical Method to the madness : Porous lamellar structure Ni(OH) 2 /RGO composites with a large capacitance are synthesized by using a facile two-step deposition/reduction method. The method promotes the deposition of more Ni(OH) 2 and full utilization of RGO. Moreover, additives are avoided. The Ni(OH) 2 /RGO composite synthesized by using the two-step method exhibits a high specific capacitance of 2877 F g −1 , long cycle life with capacitance retention of 86.5 % after 4000 cycles, and high energy density of 120.9 Wh kg −1 at a power density of 0.14 kW kg −1 . Ni(OH) 2 /RGO composite are synthesized though a facile two-step method, in which the Ni(OH) 2 deposition and GO reduction processes take place separately. The present methods promote the deposition of more Ni(OH) 2 and full utilization of RGO, owing to the high reactivity, good solubility, and dispersity of GO. Moreover, the utilization of additives is avoided. The Ni(OH) 2 /RGO synthesized by using the two-step method shows a uniform porous lamellar structure with a high specific surface area. When employed as a supercapacitor electrode material, the Ni(OH) 2 /RGO composite exhibits a high specific capacitance of 2877 F g −1 , long cycle life with capacitance retention of 86.5 % after 4000 cycles, and high energy density of 120.9 Wh kg −1 at a power density of 0.14 kW kg −1 . The Ni(OH) 2 /RGO composite prepared by using the two-step method in this work shows 11.8–85.1 % higher specific capacitances than composites fabricated by using the other method. The excellent performances and the facile synthesis method highlight the promising potential of the present Ni(OH) 2 /RGO composite in supercapacitor applications.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2014
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IF 2.726
Yue Yang,Shengming Xu,Ming Xie,Yinghe He,Guoyong Huang,Youcai Yang
Spherical Ni 1/3 Co 1/3 Mn 1/3 (OH) 2 agglomerates were synthesized by the co-precipitation method in the presence of ammonia. The results show that the growth mechanism of spherical agglomerates follows three-stages, i.e. nucleation and anisotropic growth of single crystals; agglomeration of polycrystalline crystallites agglomerated by single crystal grains as primary particles to form embryonic agglomerates; formation, growth and consolidation of spherical agglomerates or particles by agglomeration of embryonic agglomerates, continued growth of individual crystals in the agglomerates and further attachment of primary particles. The first two stages are very fast while the last stage takes almost the entire process to complete. The main reason for the anisotropic growth of Ni 1/3 Co 1/3 Mn 1/3 (OH) 2 crystal is that crystal surface energy of E (001) , E (100) , E (101) and E (102) is different with E (001) being the highest. The morphology of the final spherical agglomerates is explained by partial re-crystallization of contacting primary particles. The growth process of spherical agglomerates was examined by X-ray diffraction, scanning electron microscope, transmission electron microscope and calculation of crystal surface energy using density function theory.
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BMC Complementary and Alternative Medicine
·
2017
·Vol. 17
·期 1
·1-11
·
IF 2.288
Jiang Qian,Li Xican,Tian Yage,Lin Qiaoqi,Xie Hong,Lu Wenbiao,Chi Yuguang,Chen Dongfeng
Background
Mori Fructus and Mori Ramulus are two traditional Chinese herbal medicines from mulberries. The present work explores their beneficial effects on •OH–treated mesenchymal stem cells (MSCs) and discusses possible mechanisms.Methods Lyophilized aqueous extracts of Mori Fructus (LAMF) and Mori Ramulus (LAMR) were prepared and analyzed using HPLC. LAMF and LAMR (along with morin) were further investigated for their effects on •OH-treated MSCs using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl (MTT) assay. The direct antioxidation mechanisms were studied using 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO•)-scavenging, 2,2′-azino-bis (3-ethylbenzo-thiazoline-6-sulfonic acid (ABTS+•)-scavenging and 1,1-diphenyl-2-picryl-hydrazl (DPPH•)-scavenging, as well as Cu2+-reducing and Fe3+-reducing antioxidant power. Finally, the indirect antioxidant mechanism was investigated based on the UV-vis spectra of Fe2+-chelation.Results In each LAMF and LAMR, seven phytophenols were successfully measured by HPLC, including five flavonoids (morin, rutin, astragalin, isoquercitrin and luteolin) and two non-flavonoids (chlorogenic acid and maclurin). MTT assays revealed that LAMF, LAMR and morin could effectively increase the survival of •OH-treated MSCs at 10–100 μg/mL, and could effectively scavenge PTIO• (IC 50 6609.7 ± 756.6, 4286.9 ± 84.9 and 103.4 ± 0.9 μg/mL, respectively), DPPH• (IC 50 208.7 ± 3.0, 97.3 ± 3.1 and 8.2 ± 0.7 μg/mL, respectively) and ABTS+• (IC 50 73.5 ± 5.8, 34.4 ± 0.1 and 4.2 ± 0.2 μg/mL, respectively), and reduce Cu2+ (IC 50 212.5 ± 7.0, 123.2 ± 0.9 and 14.1 ± 0.04 μg/mL, respectively) & Fe3+ (IC 50 277.0 ± 3.1, 191.9 ± 5.2 and 5.0 ± 0.2 μg/mL, respectively). In the Fe2+-chelating assay, the five flavonoids produced much stronger shoulder-peaks than the two non-flavonoids within 420–850 nm.Conclusion
Mori Fructus and Mori Ramulus, can protect MSCs from •OH-induced damage. Such beneficial effects can mainly be attributed to the antioxidant action of phytophenols, which occurs via direct (ROS-scavenging) and indirect mechanism (Fe2+-chelating). The ROS-scavenging mechanism, however, include at least a H+-transfer and an electron-transfer (ET), and possibly includes a hydrogen-atom-transfer (HAT). In the Fe2+-chelating, flavonoids are more effective than non-flavonoids. This can be attributed to several adjacent planar chelating-sites between the 3-OH and 4-C = O, between the 4-C = O and 5-OH, or between the 3′-OH and 4′-OH in flavonoids. Such multiple-Fe2+-chelating reactions cause overlap in the UV-vis absorptions to deepen the complex color, enhance the peak strength, and form shoulder-peaks. By comparison, two non-flavonoids with catechol moiety produce only a weak single peak.
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ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2024
·
IF 10.8
Yibing Xie,Xueqian Wang,Zan Qu,Ping Ning,Langlang Wang,Haomiao Xu,Wenjun Huang,Jichang Lu,Jianfei Luo
The transformation of toxic arsine (AsH3) gas into valuable elemental arsenic (As0) from industrial exhaust gases is important for achieving sustainable development goals. Although advanced arsenic removal catalysts can improve the removal efficiency of AsH3, toxic arsenic oxides generated during this process have not received adequate attention. In light of this, a novel approach for obtaining stable As0 products was proposed by performing controlled moderate oxidation. We designed a tailored Ni-based catalyst through an acid etching approach to alter interactions between Ni and NaY. As a result, the 1Ni/NaY-H catalyst yielded an unprecedented proportion of As0 as the major product (65%), which is superior to those of other reported catalysts that only produced arsenic oxides. Density functional theory calculations clarified that Ni species changed the electronic structure of oxygen atoms, and the formed [NiIII–OH (μ-O)] active centers facilitated the adsorption of AsH2*, AsH*, and As* reaction intermediates for As–H bond cleavage, thereby decreasing the direct reactivity of oxygen with the arsenic intermediates. This work presents pioneering insights into inhibiting excessive oxidation during AsH3 removal, demonstrating potential environmental applications for recovery of As0 from toxic AsH3.
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Surfaces and Interfaces
·
2024
·
IF 5.7
Hele Hua,Nan Zhang,Zhidan Wang,Rui Li,Yunfang Wang,Jianxin Liu,Peide Han,Caimei Fan,Yawen Wang
Electrocatalytic NO 3 − reduction reaction (NO 3 RR) has attracted much attention as a promising NH 3 synthesis pathway, and Cu-based catalysts have been proven to lead to advantages in nitrate reduction . However, the active hydrogen (H*) produced by the Cu-based catalyst is insufficient to satisfy the hydrogenation process of the NO 3 RR intermediate, resulting in a large generation of NO 2 − . In this paper, the Co(OH) 2 /Cu 2 O heterojunction was constructed to improve the kinetics of H 2 O dissociation to generate H* and Co(OH) 2 /Cu 2 O (5.87 %) showed lower faradaic efficiency (FE) of NO 2 − than Cu 2 O (50.95 %). Mechanistic studies reveal that the introduction of Co(OH) 2 can help Cu 2 O lower the energy barrier of H 2 O dissociation, greatly boosting the supply of active hydrogen (H*). Not only that, but the reaction energy barriers of *NO to *NOH can be greatly reduced. The final twofold reason works together to greatly improve the efficiency of hydrogenation of NO 2 − , largely solving the problem of FE reduction due to the delayed consumption of NO 2 − , thus realizing improved performance.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2024
·
IF 9.4
Yan Chen,Guojun Lv,Xuyang Zou,Shihao Su,Jiangzhang Wang,Chaoyi Zhou,Jialing Shen,Yangbin Shen,Zhongmin Liu
Dealuminated Beta zeolite has a large amount of silanol defects on its interface, which provides an ideal place for embedding metal species and creating metal active sites in a confined microenvironment. The confined metal sites as well as their surroundings are closely related to the reactant activation and transient state achievement. Hence, unraveling the confined metal sites is of great significance for the catalytic reaction process. Herein, niobium species were incorporated into the silanol defects over dealuminated Beta zeolite with a facile dry impregnation method, co-grinding the niobium precursor with dealuminated Beta zeolite support. The successful incorporation of niobium into the silanol defects for 30Nb-Beta zeolite was verified by DRIFT, 1 H MAS NMR, UV–Vis and UV-Raman characterizations. XAS characterization and DFT calculations further disclosed that the confined Nb species existed as (SiO) 2 Nb(OH)(=O), containing two Si−O−Nb bonds, one Nb=O bond as well as one Nb−OH bond. The synthesized 30Nb-Beta zeolite catalyst displayed a superior cyclohexene conversion of 51.1%, cyclohexene oxide selectivity of 83.1% as well as TOF value of 188.2 h −1 ascribed to the inherent electrophilicity of Nb(V) for confined (SiO) 2 Nb(OH)(=O) species as well as the low oxygen transfer energy barrier for Nb V −OOH species. Furthermore, the prepared 30Nb-Beta zeolite can be effectively employed to other cyclic alkene epoxidation reactions.
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CHEMICAL ENGINEERING JOURNAL
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2024
·
IF 13.3
Zhijia Liao,Ninghao Chu,Zhenyu Yuan,Yanbai Shen,Fanli Meng
This study successfully synthesized “silver ear-like” Co(OH)F using 15 nm SiO 2 spheres as seeds. Gas sensitivity of Co(OH)F with and without SiO 2 spheres to toluene was compared at different annealing temperatures. The results demonstrate that the Co(OH)F-Si-350 sensor exhibits optimal gas sensitivity to toluene, with a response of 35 (R g /R a ) to 100 ppm of toluene at 220℃, with response and recovery times of 50 s and 80 s, respectively. Notably, the sensor detected toluene concentrations as low as 50 ppb, indicating good sensitivity to low concentrations. These findings suggest that the structural transformation resulting from the introduction of SiO 2 nanospheres, forming ultra-thin nanosheet clusters (∼12 nm), provides abundant active sites, effectively promoting substance diffusion and adsorption/desorption processes. Additionally, the incorporation of fluorine enhances the Lewis acidity of the material, facilitating the formation of stable adsorption states for gas molecules on the surface. These results reveal the significant impact of the structural transformation caused by the introduction of SiO 2 nanospheres on gas sensitivity, providing a strong theoretical foundation for further optimizing gas sensor design.
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