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Exfoliation of amorphous phthalocyanine conjugated polymers into ultrathin nanosheets for highly efficient oxygen reduction

Journal Article


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Abstract


  • It is a significant challenge to develop a high-efficiency synthetic methodology to access fully conjugated 2D conjugated polymer (CP)/covalent organic framework (COF) nanosheets (NSs) that have great application potential for electronics and energy. Herein, we report the exfoliation of a series of amorphous ethynyl-linked phthalocyanine (Pc) CPs (MPc-CPs, M = Fe, Co, Fe0.5Co0.5) into ultrathin MPc-CP NSs. Random coupling between the four regioisomers (with D4h, D2h, C2v and Cs symmetry) of the two tetra-β-substituted phthalocyanine precursors endows the resulting phthalocyanine conjugated polymers MPc-CPs with intrinsic structural defects and a disordered framework on individual layers. This in turn induces a diminished interlayer overlapping and a weakened interlayer π–π stacking interaction, facilitating the possible exfoliation of MPc-CPs into ultrathin 2D NSs with a yield of over 50%. The direction observation by transmission electron microscopy (TEM) and atomic force microscopy (AFM) demonstrates that the ultrathin MPc-CP NSs possess a smooth surface with a uniform thickness of 1–3 nm and a lateral size of hundreds of nanometers. The as-prepared bimetallic Fe0.5Co0.5Pc-CP NSs were further used to fabricate a heterostructure Fe0.5Co0.5Pc-CP NS@G with graphene NSs as an oxygen reduction reaction (ORR) catalyst, which exhibits an onset potential of 1006 mV and a half-wave potential of 927 mV in 0.1 M KOH, representing one of the best values in an alkaline medium. Moreover, the excellent ORR activity of the exfoliated tetrapyrrole-based conjugated NSs hybridized with graphene has also been demonstrated by a Zn–air battery device, showing an open circuit voltage of 1.34 V and a peak power density of ca. 180 mW cm−2.

Authors


  •   Liu, Wenping (external author)
  •   Wang, Chiming (external author)
  •   Zhang, Lijie (external author)
  •   Pan, Houhe (external author)
  •   Liu, Wenbo (external author)
  •   Chen, Jun
  •   Yang, Dongjiang (external author)
  •   Xiang, Yanjuan (external author)
  •   Wang, Kang (external author)
  •   Jiang, Jianzhuang (external author)
  •   Yao, Xiangdong (external author)

Publication Date


  • 2019

Citation


  • Liu, W., Wang, C., Zhang, L., Pan, H., Liu, W., Chen, J., Yang, D., Xiang, Y., Wang, K., Jiang, J. & Yao, X. (2019). Exfoliation of amorphous phthalocyanine conjugated polymers into ultrathin nanosheets for highly efficient oxygen reduction. Journal of Materials Chemistry A, (7), 3112-3119.

Scopus Eid


  • 2-s2.0-85061545151

Ro Full-text Url


  • https://ro.uow.edu.au/cgi/viewcontent.cgi?article=5287&context=aiimpapers

Ro Metadata Url


  • http://ro.uow.edu.au/aiimpapers/4232

Number Of Pages


  • 7

Start Page


  • 3112

End Page


  • 3119

Issue


  • 7

Place Of Publication


  • United Kingdom

Abstract


  • It is a significant challenge to develop a high-efficiency synthetic methodology to access fully conjugated 2D conjugated polymer (CP)/covalent organic framework (COF) nanosheets (NSs) that have great application potential for electronics and energy. Herein, we report the exfoliation of a series of amorphous ethynyl-linked phthalocyanine (Pc) CPs (MPc-CPs, M = Fe, Co, Fe0.5Co0.5) into ultrathin MPc-CP NSs. Random coupling between the four regioisomers (with D4h, D2h, C2v and Cs symmetry) of the two tetra-β-substituted phthalocyanine precursors endows the resulting phthalocyanine conjugated polymers MPc-CPs with intrinsic structural defects and a disordered framework on individual layers. This in turn induces a diminished interlayer overlapping and a weakened interlayer π–π stacking interaction, facilitating the possible exfoliation of MPc-CPs into ultrathin 2D NSs with a yield of over 50%. The direction observation by transmission electron microscopy (TEM) and atomic force microscopy (AFM) demonstrates that the ultrathin MPc-CP NSs possess a smooth surface with a uniform thickness of 1–3 nm and a lateral size of hundreds of nanometers. The as-prepared bimetallic Fe0.5Co0.5Pc-CP NSs were further used to fabricate a heterostructure Fe0.5Co0.5Pc-CP NS@G with graphene NSs as an oxygen reduction reaction (ORR) catalyst, which exhibits an onset potential of 1006 mV and a half-wave potential of 927 mV in 0.1 M KOH, representing one of the best values in an alkaline medium. Moreover, the excellent ORR activity of the exfoliated tetrapyrrole-based conjugated NSs hybridized with graphene has also been demonstrated by a Zn–air battery device, showing an open circuit voltage of 1.34 V and a peak power density of ca. 180 mW cm−2.

Authors


  •   Liu, Wenping (external author)
  •   Wang, Chiming (external author)
  •   Zhang, Lijie (external author)
  •   Pan, Houhe (external author)
  •   Liu, Wenbo (external author)
  •   Chen, Jun
  •   Yang, Dongjiang (external author)
  •   Xiang, Yanjuan (external author)
  •   Wang, Kang (external author)
  •   Jiang, Jianzhuang (external author)
  •   Yao, Xiangdong (external author)

Publication Date


  • 2019

Citation


  • Liu, W., Wang, C., Zhang, L., Pan, H., Liu, W., Chen, J., Yang, D., Xiang, Y., Wang, K., Jiang, J. & Yao, X. (2019). Exfoliation of amorphous phthalocyanine conjugated polymers into ultrathin nanosheets for highly efficient oxygen reduction. Journal of Materials Chemistry A, (7), 3112-3119.

Scopus Eid


  • 2-s2.0-85061545151

Ro Full-text Url


  • https://ro.uow.edu.au/cgi/viewcontent.cgi?article=5287&context=aiimpapers

Ro Metadata Url


  • http://ro.uow.edu.au/aiimpapers/4232

Number Of Pages


  • 7

Start Page


  • 3112

End Page


  • 3119

Issue


  • 7

Place Of Publication


  • United Kingdom