查找使用阿拉丁产品的科研文献

Optimized Ni, Co, Mn Oxides Anchored on Graphite Plates for Highly Efficient Overall Water Splitting

Jie Lin,Yihong Ding,Huile Jin,Tianbiao Zeng

Nickel, cobalt, and manganese oxides are easily obtainable non-noble metal catalysts for water splitting. However, the relationship between composition and catalysts’ performance still needs systematic studies. Herein, guided by theoretical calculations, a low overpotential, easily prepared Mn-doped Co3O4was deposited on graphite plates for water splitting. The 30% Mn-doped Co3O4(Co2.1Mn0.9O4) required the lowest overpotential for oxygen evolution reaction (OER), in which the Co2.1Mn0.9O4reached 20, 30, and 50 mA cm−2in the overpotentials of 425, 451, and 487 mV, respectively, with 90% IR compensation. Under overall water-splitting conditions, the current density reached 30 mA cm−2at an overpotential of 0.78 V without IR compensation. Charge density difference analysis illustrates that doped Mn provides electrons for O atoms, and that Mn doping also promotes the electron fluctuation of Co atoms. XPS analysis reveals that Mn-doping increases the chemical valence of the Co atom, and that the doped Mn atom also exhibits higher chemical valence than the Mn of Mn3O4, which is advantageous to boost the form of based-OOH* radical, then decrease the overpotential. Considering the particular simplicity of growing the Co2.1Mn0.9O4on graphite plates, this work is expected to provide a feasible way to develop the high-performance Co-Mn bimetallic oxide for water splitting.Keywords:water splitting;bimetallic oxides;Mn-doped Co3O4;DFT calculation

Assembling Co clusters via nanosized ZIF-67 sprouted from CoAl-LDH nanoflower for selective hydrogenation

Huiling Zhang,Xiaomei Zhou,Longxin Liu,Fujun Lan,Teng Zhao,Mo Qiu,Qingxin Guan,Wei Li

Atomically dispersed cluster catalysts own versatile applications in biomass valorization, while the controllable assembly and microenvironmental regulation remain a crucial challenge. Herein, Co clusters assembled via nanosized ZIF-67 sprouted from Co-Al layered double hydroxide nanoflowers were applied for selective hydrogenation of furfural (FAL). The pyrolysis temperature can tune the microstructures and acid properties of the catalyst, which accounts for the hydrogenation of FAL to furfuryl alcohol (FOL), 2-methylfuran (2-MF), and tetrahydrofurfuryl alcohol (THFOL) with yield of 99.1 %, 96.7 %, and 82.3 %, respectively. The Co clusters favor C O bond adsorption via bridging-type adsorption mode while suppressing the furan ring adsorption. Moreover, ultra-dispersed Co clusters facilitate the cleavage of C-OH bonds in FOL intermediate, leading to a high 2-MF yield. As the pyrolysis temperature increase, the formed Co nanoparticles are conducive to the parallel adsorption of FAL, resulting in the production of THFOL. This work affords a multi-functional catalyst in catalytic biomass upgrading.

Syntheses, crystal structure and properties of two chalcogenidoantimonates Mn(en)3Sb2S4 and Co(en)3Sb2Se4

Lirong Zhang,Na Li,Gele Teri,Muge Shele,E. Namila,Sagala Bai,Menghe Baiyin

Two chalcogenidoantimonates Mn(en) 3 Sb 2 S 4 ( 1 ) and Co(en) 3 Sb 2 Se 4 ( 2 ) have been synthesized in solvothermal conditions. 1 and 2 are consist of transition metal complex cations and [Sb 2 Q 4 ] 2- (Q = S, Se) anions. They have band gaps of 2.20 eV and 2.25 eV, respectively, indicating that they can be used as semiconductor materials. The photocurrent responses of 1 and 2 were also investigated. Photocatalytic experiments showed that both 1 and 2 could degrade methylene blue (MB) upon visible light irradiation, reaching 47 % for 1 and 30 % for 2 , indicating that both compounds are good photocatalytic materials. Therefore, they present a promising potential for the photoelectric research chalcogenides.

Interface and doping engineering of Co-based electrocatalysts for enhanced oxygen reduction and evolution reactions

Fangfang Fan,Qiulan Huang,Karuppasamy Kohila Rani,Xinglan Peng,Xiaotian Liu,Limin Wang,Zhongyun Yang,Dujuan Huang,Rajkumar Devasenathipathy,Du-Hong Chen,Youjun Fan,Wei Chen

The fabrication of highly efficient bifunctional catalyst for oxygen evolution/reduction reaction (OER/ORR) is essential for high performance rechargeable Zn-air batteries. Herein, we present a method of simultaneous interface/doping engineering to prepare bifunctional oxygen electrocatalyst for rechargeable Zn-air batteries. The Fe-Co 2 P/Co heterostructure was covered by N-doped carbon boxes (Fe-Co 2 P/Co@NC), and the surface electronic structure of Fe-Co 2 P/Co@NC was tailored through the controlled co-doping of P and Fe. Theoretical calculation revealed a significant charge accumulation at the interface of Fe-Co 2 P and Co, demonstrating a strong synergy in Fe-Co 2 P/Co@NC catalyst. The as-prepared Fe-Co 2 P/Co@NC catalyst exhibited an excellent catalytic performance for ORR/OER as well as rechargeable Zn-air batteries with large power density (783 mA h g Zn −1 ), high open circuit voltage (1.54 V) and long charge/discharge stability (155 h). This work provides a new approach for the construction of interface-rich heterostructure electrocatalysts for oxygen catalysis.

A Wearable Co-Located Neural-Mechanical Signal Sensing Device for Simultaneous Bimodal Muscular Activity Detection

Tiantong Wang,Yunbiao Zhao,Qining Wang

Facile Synthesis of Ni-Co LDH Nanocages with Improved Electrocatalytic Activity for Water Oxidation Reaction

Changshui Wang,Jiahui Zhang,Caiyan Shi,Dandan Cai

The development of an inexpensive, efficient and robust water oxidation catalyst is important to achieve water splitting for renewable energy production. Herein, nickel-cobalt layered double hydroxides (Ni-Co LDHs) were rationally synthesized by a facile method and can be served as efficient electrocatalysts for water oxidation. For comparison, Ni-Co LDH nanoflowers have also been synthesized by controlling the synthetic process. The composition and morphologies of the catalysts were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) and X-ray photoelectron spectroscopy (XPS). The as-obtained Ni-Co LDH nanocages exhibit a high catalytic activity toward the water oxidation reaction (WOR). The electrochemical results show that the overpotential of Ni-Co LDH nanocages electrode was 350 mV at a catalytic current density of 10.0 mA cm -2 in 1.0 M KOH. Moreover, the Tafel slope was as low as ~ 93 mV dec -1 . The unusual catalytic properties of Ni-Co LDH nanocages could be attributed to the hollow structure and the synergetic effect between Ni metal and Co metal.

Facile Synthesis of Ni-Co Double Hydroxide on Carbonized Cotton Cloth for High Performance Supercapacitor

Yanni Shen,Xueli Miao,Dandan Song,Yanting Li,Yuning Qu,Jianguo Yu,Jiajun Tang,Hao Qin,Lili Wang,Jiahao Ren,Bing Wang

A facile and novel one-step hydrothermalmethod was provided for the preparation of Ni-Co double hydroxides (NC-DH), which was directly grown on carbonized cotton cloth (CCC) and used as advanced binder-free electrodes for supercapacitors. The effect of different concentration of Ni 2+ and Co 2+ in the intial reactant (C-Ni-x-Co-y) on microstructure and electrochemical performance were studied. The results showed that flake-like structure grown uniformly under an appropriate concentration, which was benefit to improve the electrochemical performance. The electrochemical tests revealed that the C-Ni-4-Co-8 electrode displayed the maximum specific capacitance of 4.19 F cm -2 when the current density was 5 mA cm-2and excellent rate capability maintained at 3.05 F cm -2 even at the high current density of 80 mA cm -2 . The electrodes of Ni-Co double hydroxides anchored on flexible conductive substrates with excellent electrochemical properties could be obtained by cost-effective method, which could be ascribed as a highly promising potential electrode material for energy storage devices.

Electrochemical urea synthesis by co-reduction of CO2 and nitrate with FeII-FeIIIOOH@BiVO4 heterostructures

Hua-Qing Yin,Zuo-Shu Sun,Qiu-Ping Zhao,Lu-Lu Yang,Tong-Bu Lu,Zhi-Ming Zhang

Traditional urea synthesis under harsh conditions is usually associated with high energy input and has aroused severe environmental concerns. Electrocatalytic C–N coupling by converting nitrate and CO 2 into urea under ambient conditions represents a promising alternative process. But it was still limited by the strong competition between nitrate electrochemical reduction (NO 3 ER) and CO 2 electrochemical reduction (CO 2 ER). Here, Fe II -Fe III OOH@BiVO 4 - n heterostructures are constructed through hydrothermal synthesis and exhibited superior performance toward urea electrosynthesis with NO 3 − and CO 2 as feedstocks. The optimized urea yield and Faradaic efficiency over Fe II -Fe III OOH@BiVO 4 -2 can reach 13.8 mmol h −1 g −1 and 11.5% at −0.8 V vs. reversible hydrogen electrode, which is much higher than that of bare FeOOH (3.2 mmol h −1 g −1 and 1.3%), pristine BiVO 4 (2.0 mmol h −1 g −1 and 5.4%), and the other Fe II -Fe III OOH@BiVO 4 - n ( n  = 1, 3, 5) heterostructures. Systematic experiments have verified that BiVO 4 and FeOOH are subreaction active sites towards simultaneous CO 2 ER and NO 3 ER, respectively, achieving co-activation of CO 2 and NO 3 − on Fe II -Fe III OOH@BiVO 4 -2. Moreover, the urea synthesis via the *CO and NO* intermediates and C–N coupling was confirmed by the in situ Fourier transform infrared spectroscopy. This work not only alleviates the CO 2 emission and nitrate pollution but also presents an efficient catalyst for synergistic catalysis towards sustainable urea synthesis.

Alkylamine-Confined Thickness-Tunable Synthesis of Co(OH)2-CoO Nanosheets toward Oxygen Evolution Catalysis

Chuansheng He,Linlin Yang,Xiaohui Peng,Shangheng Liu,Jia Wang,Chengyuan Dong,Delin Du,Leigang Li,Lingzheng Bu,Xiaoqing Huang

Thickness regulation of transition metal hydroxides/oxides nanosheets with superior catalytic properties represents a promising strategy to enhance catalytic performance, but it remains an enormous challenge to achieve precise control, especially when it comes to the ultrathin limit (several atomic layers). In this work, a facile strategy of alkylamine-confined growth is proposed for the synthesis of thickness-tunable metal hydroxide/oxide nanosheets. Specifically, ultrathin cobalt hydroxide and cobaltous oxide hybrid (Co(OH)2-CoO) nanosheets (Co–O NSs) with a thickness in the range of 2–6 nm (5–13 atomic layers) are synthesized by using alkylamines with different carbon chain lengths as the ligand to modulate vertical coordination ability. Co–O NSs with a thickness of 2 nm (Co–O NSs-2 nm) exhibit excellent oxygen evolution reaction (OER) performance with an overpotential of 278 mV at 10 mA/cm2. The maximized number of active sites including oxygen vacancies, optimal adsorption strength, and the highest electrical conductivity are considered as the potential factors contributing to the excellent OER performance of Co–O NSs-2 nm. This work holds great significance for the precise thickness-tunable synthesis of transition metal layered hydroxide nanosheets with modulated and improved catalytic performance.

Nitrogen and oxygen co-doped graphite felt gas diffusion electrodes for efficient hydrogen peroxide electrosynthesis

Muyao Li,Zhaolian Zhu,Shiyu Yuan,Liya Ji,Tianhe Zhao,Yan Gao,Hailing Wang

In order to improve the efficiency and reusability of gas diffusion electrodes for hydrogen peroxide (H 2 O 2 ) electrosynthesis, we modified the graphite felt with nitric acid and constructed nitrogen-oxygen co-doped graphite felt/polytetrafluoroethylene/gas diffusion electrodes. The graphite felts before and after nitric acid modification were characterized by SEM, contact angle measurements, FTIR, and XPS, which showed that nitric acid modification resulted in a significant increase of oxygen- and nitrogen-containing functional groups (such as carboxyl groups and pyridinic nitrogen), which could improve the H 2 O 2 yield and current efficiency. The H 2 O 2 yield of the electrode prepared under the optimized modification conditions can reach 42.2 mg·L −1 ·cm −2 , and the current efficiency can be maintained at about 80.0%. The electrode shows relatively stable performance of H 2 O 2 electrogeneration during 13 cycles, and has a promising application prospect.

Synthesis and Characterization of Co-Modified Polyurethane Nanocomposite Latexes by Terminal and Pendant Fluoroalkyl Segments

Hua Jin,Fuquan Deng,Wei Xu

To further improve the hydrophobic and thermal properties of fluorinated polyurethane (FPU), we initially prepared the fluorine- and silicon-containing pendant groups’ diols (DEFA and DESiA) by Michael addition reaction. Next, we synthesized a series of co-modified polyurethane nanocomposite (TPFPU-SiO2) latexes by terminal and pendant fluoroalkyl segments via varying the additive amount of silica sols. Structure and performance properties of the target materials were characterized by IR, TEM, TGA, DSC, XRD, XPS, SEM, AFM, and contact angle measurements. Results showed that with the increase in silica sols dosage, the mean particle size of the TPFPU-SiO2latexes was increased and their emulsion stability gradually decreased. The thermal stability of the TPFPU-SiO2films were gradually increased and hydrophobicity of the TPFPU-SiO2films increased first and then slightly decreased. The maximum water contact angle on the TPFPU-SiO2films was 119.8° and the lowest water absorptivity was 2.49%. Thus, these novel fluorinated polyurethane nanocomposite latexes can find valuable applications in heat-resistant and anti-fouling coatings.Keywords:fluorinated polyurethane;nanocomposite;hydrophobicity;thermal behaviors

HER performance of Ni3Se2/Fe, Ni3Se2/Co and Ni3Se2/Mo composite materials with multistage structure

Guo-li Chen,Huai-yao Wang,Yong-zhi Liu,Xiao-ming Huang,Guang-ming Yin

In this paper, nanowool ball Ni 3 Se 2 , rod NiSe and multistage Ni 3 Se 2 were prepared. Multilevel Ni 3 Se 2 was doped with Fe, Co and Mo respectively to prepare composite catalysts. The prepared materials were characterized by UV, XRD, SEM-EDS and XPS . The results show that the composite catalysts with multi-level Ni 3 Se 2 and Mo have special morphology and high purity. The HER performance of the composites was tested using an electrochemical workstation, and the results show that at a current density of 10 mA cm −2 , the overpotentials of Ni 3 Se 2 , Ni 3 Se 2 /Fe, Ni 3 Se 2 /Co and Ni 3 Se 2 /Mo are 71, 71, 3 and 37 mV, respectively; At a current density of 100 mA cm −2 , their overpotentials are 396.9, 373.6, 321.8 and 290.1 mV, respectively. Their Tafel slopes are 227, 169, 145 and 137 mV dec −1 , respectively. The R ct s of Ni 3 Se 2 , Ni 3 Se 2 /Fe, Ni 3 Se 2 /Co and Ni 3 Se 2 /Mo are 1.63, 1.47, 1.15 and 0.90Ω, respectively. After the comparison of the electrochemical HER performance, it is found that the Ni 3 Se 2 /Mo composite catalyst has good HER performance.