ACS Applied Materials & Interfaces
·
2020
·
IF 8.758
Yuehan Cao,Ruiyang Zhang,Tianli Zhou,Shengming Jin,Jindi Huang,Liqun Ye,Zeai Huang,Fang Wang,Ying Zhou
Limited by the chemical inertness of CO2 and the high dissociation energy of the C═O bond, photocatalytic CO2 conversion is highly challenging. Herein, we prepare ultrathin oxygen-modified h-BN (O/BN) nanosheets containing B–O bonds. On the O/BN surface, CO2 can be chemically captured and is bonded with the B–O bond, leading to the formation of an O–B–O bond. This new chemical bond acting as an electron-delivery channel strengthens the interaction between CO2 and the surface. Thus, the reactants can continuously obtain electrons from the surface through this channel. Therefore, the majority of gaseous CO2 directly converts into carbon active species that are detected by in situ DRIFTS over O/BN. Moreover, the activated energies of CO2 conversion are significantly reduced with the introduction of the B–O bond evidenced by DFT calculations. As a result, O/BN nanosheets present an enhanced photocatalytic CO2 conversion performance with the H2 and CO generation rates of 3.3 and 12.5 μmol g–1 h–1, respectively. This work could help in realizing the effects of nonmetal chemical bonds in the CO2 photoreduction reaction for designing efficient photocatalysts.
研究领域:
材料科学
·
环境科学
✓ 已验证
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Kang-Hui Hu,Chao-Qiong Zhu,Bao-Ping Zheng,Lang Qiu,Fang Wan,Yang Song,Ben-He Zhong,Zhen-Guo Wu,Xiao-Dong Guo
Li-rich Mn-based oxide cathodes are one of the most promising cathode candidates for high energy density over 400 Wh kg −1 , deriving from oxygen redox of Li-O-Li configuration. However, the deep oxygen oxidation would lead to the formation of peroxides and superoxides (O 2 n − , 0 < n ≤ 2) and even oxygen (O 2 ), accompanied by crystal phase transformation and structure collapse. Herein, an integrative strategy of simultaneously regulating the right amount of oxygen vacancies (OVs) and B-atom doping is proposed to achieve differentially modification of both R-3 m and C2/m phases. Firstly, Rietveld refinement, HRTEM and in situ XRD results reveal that the linear increase of OVs content is achieved by regulating the amount of BN and the selective introduction of OVs inside the C2/m phase makes the oxygen partial pressure lower in the weak O-Li-O bonds of TM-layer and inhibits oxygen release at over 4.5 V. Meanwhile, kinetics test shows oxygen defects would accelerate the Li + diffusion and reduce the electronic impedance driven by uneven local charge distribution. Secondly, lattice analysis shows the strong covalent B-O bonds located at the tetrahedral site not only prevent the overoxidation of the oxygen atoms at high voltage, but also hinder the migration of Mn atoms through tetrahedral sites, which effectively avoids the damage of the crystal structure. As a result, the modified cathode exhibits the excellent discharge specific capacity of 272 mA h g −1 at 0.1C, higher rate performance of 145 mA h g −1 at 5C, an outstanding capacity retention rate of 93% at 1C and lower voltage decay value of 0.43 V after 200 cycles. This promising strategy could simultaneously achieve both high energy density and superior cycling stability and help to advance industrial application of Li-rich Mn-based Cathodes.
研究领域:
材料科学
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电化学
✓ 已验证
产品关联
DOI
高影响因子
REACTIVE & FUNCTIONAL POLYMERS
·
2019
·
IF 3.074
Xiaofan Zhao,Junhua Zhang
A novel hybrid silicone foam was successfully prepared by mixing shear stiffening gel (STG) with polymethylvinylsiloxane (MVQ) using expandable microsphere as a blowing agent. Storage modulus of STG/MVQ composite foam increased from 0.045 MPa to 0.38 MPa, when the shear frequency shifted from 0.1 Hz to 100 Hz, presenting a remarkable shear stiffening characteristic. The tensile result demonstrated that the elongation at break of the hybrid foam was as high as 814%. Besides, the hybrid foam gained excellent self-healing performance due to the cold-flow feature and viscous state of STG. More importantly, the drop hammer test indicated the safeguarding performance enhanced as the STG contents increased, with the residual peak force decreasing from 36.72 KN to 31.50 KN. In addition, a possible mechanism was proposed that it was the dynamic “B O bonds” that played a significant role in shear stiffening.
研究领域:
材料科学
·
力学
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产品关联
DOI
高影响因子
TALANTA
·
2018
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IF 4.244
Na Xiao,Shi Gang Liu,Shi Mo,Na Li,Yan Jun Ju,Yu Ling,Nian Bing Li,Hong Qun Luo
p -Nitrophenol ( p -NP) contaminants seriously endanger environmental and living beings health, hence to establish a sensitive and selective method is of great importance for the determination of p -NP. In this work, boron and nitrogen co-doped carbon dots (B,N-CDs) were synthesized by one-step hydrothermal method using 3-aminophenylboronic acid as the sole precursor. The product was characterized through high-resolution transmission electron microscopy, fluorescence spectroscopy, UV–visible absorption spectroscopy , X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. Without any functionalized modification, B,N-CDs can be directly applied as a ‘turn-off’ fluorescent probe for rapid, highly selective, and sensitive detection of p -NP. The fluorescent sensor based on the B,N-CDs exhibited a broad linear response to the concentration of p -NP in the range of 0.5 − 60 μM and 60 − 200 μM, respectively, and provided a detection limit of 0.2 μM. It was found that only the absorption spectrum of p -NP has a wide overlap with the fluorescence excitation and emission spectra of B,N-CDs compared to those of other representative analogues. The response mechanism was due to the inner filter effect and the formation of dynamic covalent B-O bonds between B,N-CDs and p -NP, which endowed the sensing platform with the rapid response and high selectivity to p -NP. Finally, the sensor showed the practicability of p -NP determination in environmental water samples.
研究领域:
环境科学
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分析化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Materials Chemistry C
·
2017
·Vol. 5
·期 11
·2826-2832
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IF 5.256
Hang Ao,Hui Feng,Xiaolu Huang,Meizhi Zhao,Zhaosheng Qian
Dynamic covalent B–O bonds are introduced to the design of a reversible fluorescence nanoswitch in response to the external stimulus of pH. This nanoswitch is based on a phenylboronic acid functionalized carbon quantum dot (PBA–CQD) nanoprobe, and constructed with reference to the two facts that the PBA–CQD probe can bind to p-nitrophenol to form a non-fluorescent conjugate via B–O bonds, and that the making and breaking of the B–O bonds between them can be controlled by pH changes. Excellent reversibility of this nanoswitch is illustrated by switching of the pH from 4 to 8. The reaction between the PBA–CQD nanoprobe and the p-nitrophenol resulting in switching off the fluorescence is further utilized to design a general detection strategy for enzyme activity when substrates that can generate p-nitrophenol through enzymatic reactions are chosen. The feasibility of the detection strategy is qualitatively assessed using α-glucosidase and β-galactosidase, and its practicability to quantitatively monitor enzyme activity is also demonstrated by taking α-glucosidase as an example. The detection limit of this method can be as low as 0.33 U L−1, which is much lower than those reported previously and is sufficiently low to be capable of α-glucosidase level detection in practical human samples. This study demonstrates excellent usability of dynamic covalent B–O bonds in the design of reversible switches and in the general detection of enzyme activity, and provides a sensitive, real-time assay for α-glucosidase based on carbon quantum dots.
研究领域:
分析化学
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生物医学工程
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酶学
✓ 已验证
产品关联
DOI
高影响因子
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