| 1. |
- Huang, Linzhe, et al.
(författare)
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Facile synthesis of hollow carbon spheres by gas-steamed bifunctional NH4F for efficient cathodes in microbial fuel cells
- 2023
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Ingår i: Carbon. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0008-6223 .- 1873-3891. ; 207, s. 86-94
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Tidskriftsartikel (refereegranskat)abstract
- A facile gas-steamed strategy is reported for preparing heteroatom dual-doped hierarchical porous hollow carbon catalysts via carbonization of a mixture of carbon sphere precursor and ammonium fluoride (NH4F). Notably, NH4F can be decomposed into NH3 and HF by pyrolysis, in which HF gas can etch SiO2 pellets to form hollow structure while the N and F atoms can be introduced at the same time. The FCS-900 exhibits admirable elec-trocatalytic properties with the highest onset potential and limiting current density in neutral electrolytes (0.944 V vs. RHE and 6.44 mA cm-2). In comparison to MFC-Pt, much higher output voltage and power density (0.617 V and 1093.6 +/- 6.26 mW m-2) are obtained by MFC-900. Such results can be attributed to the largest specific surface area of FCS-900 to supply exposed active sites and fast transportation channels. Based on X-ray photo-electron spectroscopy, the FCS-900 catalyst possesses the active substances of pyridinic/graphitic N and C-F bonds. The synergism of N and F can effectively facilitate the adsorption of O2 during ORR, as further supported by density functional theory calculation. The facile and green synthesis strategy can be extended to design metal -free carbon-based electrocatalysts with superior electrocatalytic performance.
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| 2. |
- Huang, Linzhe, et al.
(författare)
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Facile synthesis of NS@UiO-66 porous carbon for efficient oxygen reduction reaction in microbial fuel cells
- 2022
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Ingår i: Journal of Power Sources. - : ELSEVIER. - 0378-7753 .- 1873-2755. ; 544
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Tidskriftsartikel (refereegranskat)abstract
- Exploiting a facile way to synthesize low-cost and high-performance oxygen reduction reaction (ORR) catalysts is a core issue in microbial fuel cells (MFCs). Hence, a facile and extensible method has been developed to prepare efficient ORR catalysts by using robust UiO-66 as a precursor, modified with melamine and trithiocyanuric via the impregnation method. Benefiting from the hierarchical structure of UiO-66, the NS@UiO-66 has excellent stability, more active sites and improved mass transfer. Significantly, the half-wave potential and the current density of the NS@UiO-66 are 0.546 V vs. RHE and 6.19 mA cm(-2) respectively, which is better than that of benchmark Pt/C in neutral conditions. Furthermore, the power density of MFCs assembled with the NS@UiO-66 catalyst is 318.6 +/- 2.15 mW m(-2). The density functional theory calculation demonstrates that the reaction barrier can be reduced effectively for accelerating the ORR process through the synergistic effect of N and S. The NS@UiO-66, as an ideal candidate to substitute for the commercial Pt/C counterpart, is expected to promote the scaling-up production and application of MFCs due to low-cost elements doping and facilely synthetic method.
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| 3. |
- Wu, Guoqing, et al.
(författare)
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Gas exfoliation induced N, S-doped porous 2D carbon nanosheets for effective removal of copper ions by capacitive deionization
- 2023
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Ingår i: Desalination. - : ELSEVIER. - 0011-9164 .- 1873-4464. ; 565
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Tidskriftsartikel (refereegranskat)abstract
- Using capacitive deionization to remove heavy metal ions from water has received much attention, but the inferior salt adsorption capacity (SAC) of electrode materials has always limited its practical application. Herein, N, S co-doped two-dimensional (2D) porous glucose derived carbon nanosheets (NSPGC) was successfully fabricated, utilizing the gas exfoliation by calcination of thiourea. The NSPGC demonstrates distinct 2D lamellas, high specific surface area (2529 m2 g-1), hierarchical pore structure and high wettability. In electrochemical tests, a high specific capacitance (127 F g-1) and electrons/ions transport performance can be achieved in the NSPGC, moreover it showed a prominent SAC of 206.57 mg g-1 and recoverability in 100 mg L-1 CuSO4 solution. Moreover, the density functional theory (DFT) calculation manifested the intrinsic affinity of Cu2+ improved by N, S co-doping, which played an essential role in enhancing the Cu2+ removal performance of CDI. Our work provided a new insight into the preparation of high-performance CDI electrode materials for Cu2+ removal and promoted the application of CDI in heavy metal wastewater.
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| 4. |
- Zhong, Kengqiang, et al.
(författare)
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Enhanced oxygen reduction upon Ag/Fe co-doped UiO-66-NH2-derived porous carbon as bacteriostatic catalysts in microbial fuel cells
- 2021
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Ingår i: Carbon. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0008-6223 .- 1873-3891. ; 183, s. 62-75
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Tidskriftsartikel (refereegranskat)abstract
- As a promising energy storage/conversion technology, the microbial fuel cell (MFC) is generally restricted by the biofouling on the cathode and the sluggish kinetics of oxygen reduction reaction (ORR). Consequently, developing bacteriostatic and high-performance ORR catalysts is critical for the large-scale application of MFC. Herein, we prepare an electrocatalyst of porous octahedral zirconium-based metal organic framework (MOF) UiO-66-NH2 with dispersed Ag and Fe3C nanoparticles (Ag/Fe-N-C) through a facile impregnation and pyrolysis method for an efficient alkaline and neutral ORR. Systematic experimental results demonstrate that the synergistic effect of Ag and Fe can optimize the d-band center of catalyst to boost the interfacial charge transfer, thus resulting in an increased ORR kinetics. As expected, the catalyst with Ag/Fe-N-C-2:1 exhibits outstanding onset potential (1.01 V vs. RHE) and half-wave potential (0.58 V vs. RHE) in neutral electrolyte, which is comparable to Pt/C catalyst. Meanwhile, Ag/Fe-N-C-2:1 indicates obvious antibacterial activity, inhibiting the biofouling on the cathode surface. The MFC with the Ag/Fe-N-C-2:1 as the cathode catalyst can achieve a maximum power density of 1261.1 +/- 24 mW m(-3), outperforms the MFC with Pt/C (1087.5 +/- 14 mW m(-3)). In summary, Ag/Fe-N-C2:1 composite can serve as a feasible alternative cathode catalyst for MFC. (C) 2021 Elsevier Ltd. All rights reserved.
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| 5. |
- Zhong, Kengqiang, et al.
(författare)
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Facile gas-steamed synthesis strategy of N, F co-doped defective porous carbon for enhanced oxygen-reduction performance in microbial fuel cells
- 2023
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Ingår i: Journal of Power Sources. - : ELSEVIER. - 0378-7753 .- 1873-2755. ; 579
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Tidskriftsartikel (refereegranskat)abstract
- The metal-free carbon-based catalyst with low cost and high oxygen reduction reaction (ORR) activity is urgently desired to satisfy the demands of microbial fuel cells (MFCs). However, it is still a great challenge to develop a facile and feasible strategy to construct efficient active sites of heteroatom doping for carbon-based electrocatalyst. Herein, we report a strategy based on an ammonium fluoride (NH4F) gas-steamed metal-organic frameworks (MOFs) to heighten structural defects and density of N, F active sites of metal-free catalyst. Oxygen temperature-programmed deposition and density functional theory results confirm that the NH4F gas-steamed process greatly enhances the adsorption affinity of O2 and oxygen intermediates on the catalysts. The resulted N and F co-doped porous carbon cage (FNC-15) demonstrates outstanding ORR catalytic activity and long-term stability in alkaline and neutral electrolytes. This work proposes a facile and efficient in situ gas-steamed strategy to develop metal-free cathode catalysts with superior performance.
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