JOURNAL OF POLYMER SCIENCE
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2023
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IF 3.4
Changtong Song,Hongyi Shu,Xianhong Zhang,Yuhong Ma,Dong Chen,Wantai Yang
Herein, low molecular weight poly(vinyl chloride- co -n-butyl acrylate- co -vinyl acetate) (PCBV) ternary copolymers with varied copolymer composition was employed as a novel polymeric lubricant in rigid PVC. The lubrication effect of PCBVs on the melting process and mechanical properties of the final PVC products were fully investigated. The results indicated that PCBV can serve either as an internal or as an external lubricant depending on its composition. PCBV-45.5 terpolymer (PBA% ~ 45.5%) exhibits outstanding balance both internal and external lubricating roles. SEM-EDS results show that addition PCBV-45.5 form a film on the surface of PVC grains as similar as that adding both internal and external lubricants. Fusion characteristics and DMTA demonstrate that PCBV-45.5 prolongs the fusion time (26% extension, 1.5 phr) and reduces the glass transition temperature (4.0 °C, 1.5 phr). Finally, the mechanical properties of rigid PVC have been greatly improved by using 1.5 phr PCBV-45.5. In detail, the tensile strength increased from 54 to 59 MPa and the elongation at break increased from 10% to 30%, respectively. Meanwhile, the impact strength of PVC/PCBV-45.5 is 3.6 times that of the blend without addition. The excellent performance of PCBV exhibited great potential as a polymeric lubricant candidate in rigid PVC composites. Graphical
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SEPARATION AND PURIFICATION TECHNOLOGY
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2023
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IF 8.6
Yi Gao,Xinyang Tan,Guanlong Wang,Xiaoli Dong,Xiufang Zhang
The water treatment performance of membrane filtration is usually restricted via the paradox between permeability and selectivity. Herein, the nitrogen doped porous carbon supported Co catalysts (CoNPC), serving as both porous filler and peroxymonosulfate (PMS) activator, were firstly filled into polyvinylidene fluoride (PVDF) matrix to construct a novel mixed matrix catalytic membrane (CoNPC@PVDF) for enhanced water purification. Owing to the robust binding between CoNPC and PVDF, a high loading (50 wt%) and even dispersion of CoNPC were realized in CoNPC@PVDF, and its permeability and selectivity were both improved with the increase of CoNPC content. The optimum CoNPC@PVDF with PMS activation assistance (FCP) exhibited effective phenol removal at short retention time (1.5 s) and high permeability (256.6 L m −2 h −1 bar −1 ). The performance of CoNPC@PVDF FCP was 2.9 and 2.5 times higher than that of filtration alone and PMS activation alone, respectively, and even dramatically outweighed the reported catalytic membranes and heterogeneous catalysts. The outstanding performance of CoNPC@PVDF catalytic membrane was mainly attributed to its thin membrane structure and high filling degree of CoNPC, resulting in ultrahigh mass transfer rate (1.8 × 10 −4 m s −1 ) and more exposed active sites for enhanced PMS activation into radicals (mainly •OH and SO 4 •− ) towards pollutant removal.
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JOURNAL OF SOLID STATE CHEMISTRY
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2023
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IF 3.3
Zhoujie Zhang,Yuhao Li,Jiajia Zhang,Min Fang,Yong Wu
We discovered that triethanolamine (TEOA) can break Co–N bonds in a 2D Co(II)-imidazole MOF, {[Co(TIB) 2 (H 2 O) 4 ]SO 4 } (TIB stands for 1,3,5-tris(1-imidazolyl) benzene) (CoTIB) to form the ultrafine fragments of CoTIB with sizes <5.6 nm under stirring, which are highly efficient and selective (>99%) heterogenous cocatalysts for the visible-light-driven photocatalytic CO 2 reduction reaction to CO. The efficiency of the ultrafine fragments of CoTIB (2.0–4.2 nm) reaches 42.7 mmol g −1 h −1 or a TOF of 33.7 h −1 based on Co atoms, which are among the best of heterogenous cocatalyst for photocatalytic CO 2 RR to CO systems. They are also highly stable under stirring with a TON greater than 909 in 54 h. The ultrafine fragments of CoTIB in mixed solvents were obtained by filtration, using a 0.22-μm filter head, of the 9-h stirred mixture of CoTIB/CH 3 CN/TEOA/trace-H 2 O or the 9-h reaction mixture using 1.0 mg of CoTIB. The fragments of CoTIB in these filtrates were characterized by high-resolution mass spectrometry (HRMS), size distribution and Zeta-potential measurements, ICP-MS, as well as Linear-Sweep-Voltammetry (LSV) measurements. The formation process of these nanoparticles and the mechanism of the photocatalytic CO 2 RRs were proposed. In addition, this work provides an easy method for making ultrafine fragments (<10 nm) of a Co(II)-imidazole MOF or other MOFs, which could also be viewed as MOF nanoparticles or quantum dots stabilized by coordination of TEOA molecules.
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DYES AND PIGMENTS
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2021
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IF 4.889
Wenbo Bai,Guoxu Qin,Jing Wang,Lei Li,Yonghong Ni
It has drawn extensive research interest to integrate luminescent ligands into metal-organic frameworks as luminescent materials due to striking luminescent properties. In this work, a Co-MOF with weak fluorescence emission , [Co(OBA)(2,2′-BPY)], was synthesized by a mixed solvothermal route with Co(NO 3 ) 2 as the Co 2+ ion source, 4,4′-Oxybis(benzoic acid) (OBA) and 2,2′-Bipyridyl (2,2′-BPY) as the ligands. Its fluorescence was obviously enhanced through integrating a small amount of luminescent ligands: 2-aminoterephthalic acid. Interestingly, the above enhanced fluorescence could be selectively quenched by the organophosphorus pesticides with p-nitrophenyl group such as p-nitrophenyl phosphate (PNPP) and bis(p-nitrophenyl) phosphate (BNPP) in water systems. As a case, the detection limit towards PNPP was up to 352 nM (0.07 mg kg −1 ), which is far lower than the standards for similar pesticide residues in fruits in China (0.1–0.6 mg kg −1 ) [ 1 ]. At the same time, the above phenomenon of the fluorescence quenching was not interfered from some other pesticides, metallic ions, amino acids and aromatic nitrocompounds, implying the present fluorescent material has potential application as a highly selective probe for detecting PNPP pesticide residues in food and domestic water. Furthermore, a possible quenching mechanism was discussed.
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CHEMICAL ENGINEERING JOURNAL
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2021
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IF 13.273
Dong Guo,Yongqiang Wang,Chen Chen,Jiaqi He,Meilin Zhu,Jie Chen,Conglu Zhang
The synthesis of Vis-light driven catalysts with high photocatalytic performance and efficient activation of persulfate requires new strategies. Herein, a multistage structural tuning graphitic carbon nitride co-modified by Co, S (pg-C 3 N 4 /Co 3 O 4 /CoS) was synthesized for the first time through in-situ template method and microwave sulfurization treatment. A photocatalysis-PMS oxidation coupling system was also proposed. The results showed that the introduction of cobalt could improve the photocatalysis and PMS activation efficiency of the graphitic carbon nitride. Further sulfurization treatment could generate more active sites for PMS activation and increase the interlayer distance of carbon nitride to broaden the absorption range of Vis-light. Density functional theory (DFT) calculations indicated the migration of electrons from carbon nitride to CoS promoted the recycling of Co 3+ /Co 2+ . In the coupling system, BPF 50 mL (30 mg L -1 ) was degraded by 99% in 10 min with 0.1 g L -1 catalyst and 0.32 mmol L -1 PMS. The degradation rate was 4 times faster than that of pure PMS system under visible light. Notably, BPF was effectively mineralized and TOC removal rate reached 90%. The stability and recycling experiments showed that pg-C 3 N 4 /Co 3 O 4 /CoS maintained high catalytic performance under complex matrix and multiple cycles, and could be quickly separated and recovered due to the magnetic Co 3 O 4 . This work will provide a new strategy for the development of multi performance catalytic materials, and the proposed photocatalysis-PMS coupling system has huge potential for the wastewater treatment.
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JOURNAL OF POWER SOURCES
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2020
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IF 8.247
Dan Wang,Peixia Yang,Hao Xu,Jingyuan Ma,Lei Du,GuoXu Zhang,Ruopeng Li,Zheng Jiang,Yun Li,Jinqiu Zhang,Maozhong An
The Zn-air battery is a promising next-generation battery because of the higher energy density and safety compared with the Li-ion battery. However, the Zn-air battery suffers from huge energy loss and poor cycling performance, which are due to the sluggish kinetics of oxygen reduction/evolution reactions (ORR/OER) and the instability of bifunctional catalysts . The state-of-the-art bifunctional catalyst is the composite of Pt and Ir/Ru oxides, which is hindered by the scarce resource and high cost. Therefore, developing low-cost and high-efficient bifunctional non-noble metal-based catalysts is essential to the deployment of Zn-air batteries. Herein, we report a dual-nitrogen-source mediated pyrolysis route to rationally design and synthesize the hybrid Co/Co–N–C bifunctional catalyst. The tailored catalyst consisting of carbon confined Co nanoparticles and atomically dispersed Co–N–C moiety is identified. Remarkably, the dual-nitrogen-source derived Co/Co–N–C catalyst demonstrates excellent electrochemical performances with a half-wave potential of 0.882 V for ORR and a potential of 1.640 V at 10 mA cm −2 for OER; reasonably, the bifunctionality of Co/Co–N–C, which is supported by the excellent self-breathing Zn-air battery performance (the maximum energy density of 897.1 Wh kg Zn −1 ; no obvious degradation within 167h cycling). The abundant Co-Nx sites and metallic Co nanoparticles synergistically boost the ORR and OER.
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NEW JOURNAL OF CHEMISTRY
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2020
·Vol. 44
·期 22
·9522-9529
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IF 3.288
Hengbo Zhang,Fuquan Niu,Shaoyu Li,Yanhong Yin,Hongyu Dong,Hongyun Yue,Zhaoxia Cao,Shuting Yang
Highly effective bifunctional oxygen electrocatalysts play a key role in fuel cells (FCs), metal–oxygen batteries, and water splitting devices. In this paper, metal organic layer (MOL) derived Co/Co9S8 nanoparticles coated with N,S co-doped graphene-like carbon nanosheets were synthesized with the help of the space-confinement effect of montmorillonite (MMT). The as-prepared material shows excellent electrocatalytic activity both for oxygen reduction and oxygen evolution reactions in 0.1 M KOH solution: its ORR onset potential is 0.93 V (vs. RHE) and the limiting diffusion current density is 4.7 mA cm−2. Moreover, the retention of current for the as-prepared material is 85% after a stability test for 10 000 s for the ORR, while those of the template free catalyst and commercial Pt/C glided below 80%. Additionally, its Tafel slope is 265 mV dec−1, which is much smaller than that of the control sample, suggesting the excellent OER kinetics. The excellent catalytic activity and stability can be attributed to the relatively higher specific surface area, higher number of pyridinic-N and Co–Nx active sites, and higher graphitization degree compared to the template free catalyst.
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ACS Catalysis
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2020
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IF 12.35
Shangbo Ning,Hua Xu,Yuhang Qi,Lizhu Song,Qiqi Zhang,Shuxin Ouyang,Jinhua Ye
The transformation of CO2 into a single product is a critical scientific challenge because of the difficulty associated with targeted activation and conversion of CO2 by heterogeneous catalysts. Herein, we present an atomic-scale dispersed Co–N species anchored Co@C hybrid structure (entitled as Co@CoN&C) that regulates catalytic properties in thermodynamic and kinetic processes to achieve active and highly selective CO yield in the photothermal CO2 reduction. An optimal sample delivers the maximum yield rate of 132 mmol gcat.–1 h–1 and remarkable CO selectivity (91.1%), while the undesirable methanation activity, compared with typical Co nanoparticles (NPs), was suppressed. The mechanism study suggests that the strong photon–matter interaction over graphitic-carbon and Co NPs can enhance the light-to-heat conversion efficiency and thus induce the high work temperature, which is thermodynamically beneficial for CO2 activation and subsequently promoted the catalytic activity. Furthermore, the carbon layers improve the adsorption of CO2, and the surface atomically dispersed Co–N species weakens hydrogenation capability, which kinetically controls the reaction pathway and therefore attains the high selectivity for CO production. This study exemplifies that the microstructure design can modulate the thermodynamic and kinetic factors of photochemical reaction and thereby achieve potential solar-to-chemical energy conversion.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2021
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IF 5.816
Kexin Huang,Zhongyun Yang,Ling Liu,Xue Yang,Youjun Fan,Miaolan Sun,Chengzhou Liu,Wei Chen,Jun Yang
We herein propose a dual ligand coordination strategy for deriving puissant non-noble metal electrocatalysts to substitute valuable platinum (Pt)-based materials toward oxygen reduction reaction (ORR), a key reaction in metal-air batteries and fuel cells. In brief, cobalt ions are firstly double-coordinated with proportionate 2-methylimidazole (2-MeIm) and benzimidazole (BIm) to obtain drum-like zeolitic imidazolate frameworks (D-ZIFs), which are then carbonized to output the final Co, N co-doped porous carbon (Co–N–PC D ) catalyst inheriting the drum-like morphology of D-ZIFs. The Co–N–PC D is featured by mesopores and exhibits superb electrocatalytic behavior for ORR. Impressively, the half-wave potential of Co–N–PC D catalysts is 0.886 V with finer methanol-tolerance and stability than those of commercial Pt/C. Additionally, a zinc-air battery assembled from the Co–N–PC D displays an open-circuit voltage of 1.413 V, comparable to that of commercial Pt/C (1.455 V), suggesting the potentials of Co–N–PC D in practical energy conversion devices.
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ACS Applied Energy Materials
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2021
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IF 6.024
Xinyao Zou,Chao Ma,Ang Li,Zhan Gao,Zulipiya Shadike,Kun Jiang,Junliang Zhang,Zhen Huang,Lei Zhu
Electrochemical conversion of CO2 to the syngas hybrid with the Fischer–Tropsch (FT) process is a promising way to produce synthetic fuels from renewable energy sources. The product distribution in liquid hydrocarbons produced by FT synthesis has strong dependence on the CO/H2 ratio of the syngas feedstock. Herein, we demonstrated the feasibility of tuning the CO/H2 ratio at a wide range by developing nanoparticle-assisted Ni–Co binary single-atom catalysts for electrocatalytic production of syngas. By controlling the elemental proportion of Ni–Co in the composite catalysts, electrochemical reduction of CO2 to syngas with a tunable CO/H2 ratio from 0.3 to 27.6 was achieved. For the binary catalysts with a Ni–Co ratio of 1:1, the CO/H2 ratio maintains at 1.3–1.5 in a broad potential range from −0.59 to −0.83 V versus reversible hydrogen electrode (RHE) and the total current density reaches ∼32.2 mA/cm2 at −1.0 V versus RHE. The promotion effect of nanoparticles on Ni–Co single-atom catalysts was validated by partial removal of nanoparticles and further density functional theory (DFT) calculations. As revealed by DFT calculations, nanoparticles incorporated in single-atom sites take essential roles in facilitating the adsorption of CO2 and the formation of *COOH. The origin of CO2RR and hydrogen evolution reaction reactivities can be identified as Ni–N4 and Co–N4 single-atom sites, respectively. The dual active sites allow the facile control of the CO/H2 ratio of electrochemical converted syngas, and it will be beneficial to downstream production of diverse chemicals.
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ELECTROCHIMICA ACTA
·
2019
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IF 5.383
Yuanyuan Dong,Min Zhou,Lei Zhang
3D multiporous Co, N co-doped MoO 2 /MoC (3D Co,N-MoO 2 /MoC) nanorods hybrids were successfully synthesized via carburizing core-shell ZIF-67-cladded MoO 3 nanorods precursor at high temperature. As-fabricated Co,N-MoO 2 /MoC nanorods coated glassy carbon electrodes (GCE) was demonstrated to possess superior electrocatalytic activity for the electro-oxidation of acetaminophen (AC) and 4-aminophenol (4-AP). Such excellent electrochemical performance was largely attributed to the synergistic effect of the unique multiporous structure, the optimal component and abundant active sites of the nanorods. The corresponding electrode reaction mechanisms were studied in detail in this article. Under optimal conditions, the linear detection ranges were 0.05–200.0 μmol/L for AC and 0.05–140.0 μmol/L for 4-AP, respectively, with the low detection limits of 0.013 μmol/L and 0.012 μmol/L. Furthermore, the 3D Co,N-MoO 2 /MoC/GCE revealed excellent sensitivity, good reproducibility, stability and anti-interference ability. The developed electrode was evaluated towards the detecting AC and 4-AP in biological fluids, environment water and pharmaceutical formulations with satisfactory recovery, which had a broad application prospect.
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JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
·
2024
·
IF 4.3
Yinlong Qiao,Qingguo Tang,Yuanhang Han,Xinhui Duan,Jinsheng Liang,Jian-Feng Sun
Water electrolysis is considered to be one of the most promising approaches for developing sustainable energy technologies, however, the high cost and lack of stability of traditional precious metal electrocatalysts have hindered the development of the field of water electrolysis. Covalent organic polymers have greater potential for the preparation of low-cost electrocatalysts with high efficiency and long-term stability due to their low cost, controllable chemical composition, and rich pore structure. Cobalt phthalocyanine-based covalent organic polymers were loaded onto few-layer graphene by a hydrothermal method and then pyrolyzed to produce Co, N, and P co-doped few-layer graphene (Co–N/P-FG-700). Co–N/P-FG-700 demonstrates superior performance for oxygen evolution reaction (OER) due to the synergistic effect of abundant active sites and conductive carriers, with an overpotential of 358 mV at a current density of 10 mA cm −2 and 90% of the current density after 50,000 s of stability testing. Co–N/P-FG-700 exhibits excellent results for hydrogen evolution reaction (HER) with an overpotential of −275 mV at a current density of −10 mA cm −2 and a current density retention of 93% after a 50,000 s stability test. This study provides a rational pathway for the design of low-cost, high-performance, stable bifunctional OER/HER electrocatalysts.
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