Search

Highlights: [•] Catalytic carbonization of mixed plastics (including PP, PE and PS) into HCSs. [•] The diameter of mesoporous HCSs was modulated by the addition of OMMT. [•] The yield of uniform HCSs was increased by adding more Co3O4 catalyst. [•] OMMT promoted the dispersion of Co3O4 and the degradation of mixed plastics. [•] This method offers a potential way to effectively convert waste plastics into HCSs. [Copyright &y& Elsevier]

Highlights: [•] Catalytic carbonization of PE into cup-stacked carbon nanotubes (CS-CNTs). [•] Yield and morphology of CS-CNTs were modulated by the chain structure of PE. [•] The chain structure of PE significantly influenced the degradation products of PE. [•] The degradation products of PE determined the growth of CS-CNTs. [•] This one-pot approach offers a potential way to convert waste plastics into CS-CNTs. [Copyright &y& Elsevier]

[Display omitted] • A green and high-yield route to recycle waste masks into CNTs/Ni hybrids. • The yield of carbon as high as 64.4 g/100 g waste masks. • The Ni(OH) 2 /NiCl 2 as universal catalysts to catalytic carbonization waste masks form different environments. • Superior microwave absorption performances with reflection loss of -56.3 dB and absorption bandwidth of 4.3 GHz. With the worldwide pandemic of COVID-19, a tremendous amount of face masks have been consumed and discarded, resulting in serious environment pollution and infectious hazards. Herein a green and high-yield route has been developed to recycle waste masks (WMs) into CNTs/Ni hybrids via catalytic carbonization. Our results exhibited that the yield of carbon was as high as 64.4 g/100 g WMs. Furthermore, the as-fabricated CNTs/Ni hybrids were applied for microwave absorption, which displayed superior performances, including a strong reflection loss of -56.3 dB and an absorption bandwidth of 4.3 GHz with absorber thickness of only 2.0 mm. The mechanism was mainly ascribed to the favorable synergistic effects of CNTs and Ni on conduction and magnetic losses, dipolar polarization, interfacial polarization and impedance matching. Thus, this work provides an environmentally friendly, scalable and cost-effective strategy for recycling waste masks into high-valuable carbon nanomaterials, and exploits their potential application for microwave absorption. [ABSTRACT FROM AUTHOR]

Abstract: A one-pot approach to prepare Cu–Ni/C heterogeneous composites by carbonization of polypropylene (PP) using combined catalysts of Ni2O3 and CuCl was proposed. TEM, SEM, TGA and Raman measurements were performed to investigate the effects of Cl/Ni molar ratios on the yield and morphology of the resultant carbon materials. The yield of carbon materials in Cu–Ni/C first increased and then decreased as the Cl/Ni molar ratio increased, and the maximum yield was achieved at Cl/Ni molar ratio of 0.125. Longer and thinner carbon nanotubes (CNTs) were obtained at low Cl/Ni ratios while shorter carbon fibers were formed at high Cl/Ni ratios. The effect of Cl/Ni molar ratio on the active sites for the growth of carbon materials and degraded products of PP were investigated by XRD, GC and GC–MS. Interestingly, the resultant Cu–Ni/C showed the catalysis to “Click” reaction. As a result, the initial catalytic substances (Ni2O3 and CuCl) could be effectively used twice as catalysts in the carbonization of PP and in the later application of the resultant Cu–Ni/C composites. More importantly, this approach is a new potential method to transform waste polymer materials into valuable metal/carbon heterogeneous composites. [Copyright &y& Elsevier]