Liming Zhao,Lijun Guo,Yuling Tang,Jianfei Zhou,Bi Shi
Research on the rational design of photocatalysts for efficient hexavalent chromium (Cr(VI)) reduction from Cr(VI)-containing wastewater has attracted widespread attention. In this paper, a novel g-C3N4/C/Fe2O3 photocatalyst was successfully synthesized by anchoring g-C3N4 nanosheets onto C/Fe2O3 that was prepared using collagen fiber as the biochar resource following the Fe tanning mechanism to reduce Cr(VI) under artificial solar irradiation. Under the same conditions, the as-prepared g-C3N4/C/Fe2O3 photocatalyst exhibited higher Cr(VI) reduction efficiency than g-C3N4, and the Cr(VI) reduction efficiency increased as Fe content in the g-C3N4/C/Fe2O3 photocatalyst increased. The enhanced photocatalytic performance was primarily ascribed to the formation of an indirect Z-scheme heterojunction between C/Fe2O3 and g-C3N4, which improved the separation efficiency of the photogenerated charge carrier. Furthermore, radical trapping indicated that photoinduced electrons (e–) were the main factor for Cr(VI) reduction. This work provides guidance for high value-added utilization of collagen fiber in constructing efficient light-driven photocatalysts and practical Cr(VI) removal from wastewater.
Yubo Wu,Honglin Lin,Xuyun Gao,Zhiyan Liu,Yulun Nie
The Fe 3+ /Fe 2+ cycle has been identified as the rate-limiting step in the Fenton system, and many efforts have been made to promote the Fe 3+ reduction via external electrons provided by various electron donors. However, how to design an efficient electron transport pathway and then inhibit the invalid electron shuttle has been largely underestimated. In this study, two kinds of heterogeneous Fenton catalysts of CuO@Fe 2 O 3 and CuO@C@Fe 2 O 3 were prepared. The key role of carbon in transporting electrons as an electron bridge and its enhancement mechanism in photo-assisted Fenton-like performances were explored in detail. Compared with CuO@Fe 2 O 3 , the removal efficiency of tetracycline (TC) and the corresponding pseudo-first order reaction rate constants over CuO@C@Fe 2 O 3 increased significantly from 88.6 % and 0.1054 min −1 to 99.7 % and 0.2058 min −1 , respectively. Based on a series of probe experiments, visible light irradiation can promote the reduction of Cu 2+ to Cu + , then the carbon in CuO@C@Fe 2 O 3 can effectively transfer electrons from Cu + to Fe 3+ , enhancing the Fe 3+ /Fe 2+ cycle and the following Fenton-like efficiency. Since more ·OH while less ∙O 2 - was produced over CuO@C@Fe 2 O 3 , which further supports the fact that the enhanced Fe 3+ /Fe 2+ cycle was due to the transfer electron from Cu + to Fe 3+ instead of the Haber-Wiss mechanism. Hence, this study provides new insight for effectively improving the transfer efficiency and effective utilization of electrons in Fenton systems.
Wenyu Wang,Yu Feng,Shuaiguo Zhang,Miao Wang,Wei Song,Luchao Yue,Mingzheng Ge,Jie Mi
Premixed flame configuration is considered as an effective method for the synthesis of carbon materials. In this work, flexible single-walled carbon nanotube network decorated by carbon-encapsulated Fe 2 O 3 nanoparticles (C@Fe 2 O 3 /SWCNT) membrane was in-situ fabricated via a facile floating catalyst premixed ethanol flame method, and followed by annealing treatment. In this process, low-cost ethanol and ferrocene were used as carbon source and catalyst precursor for the synthesis of C@Fe 2 O 3 /SWCNT, respectively. Benefiting from the interconnected conductive network, the as-fabricated C@Fe 2 O 3 /SWCNT membrane was used as a free-standing anode for lithium-ion batteries. Structural characterization revealed that the ultrafine Fe 2 O 3 nanoparticles homogeneously anchored on the SWCNT network, which facilitates the fast diffusion for electron. Furthermore, the carbon layers uniformly enwrap on Fe 2 O 3 can effectively suppress the aggregation and buffer the volume change of Fe 2 O 3 during the lithiation/delithiation process. Consequently, this material delivered an excellent lithium storage performance with a high reversible capacity of 1294.7 mAh g −1 at 50 mA g −1 , and an excellent cyclability of 82.5% retention is obtained after cycles at 2 A g −1 . This study provides a novel low-cost and fast method for preparing flexible advanced electrode for next-generation rechargeable batteries.
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