Metal-Carbon-CNF Composites Obtained by Catalytic Pyrolysis of Urban Plastic Residues as Electro-Catalysts for the Reduction of CO2

Abstract

Metal-carbon-carbon nanofibers composites obtained by catalytic pyrolysis of urban plastic residues have been prepared using Fe, Co or Ni as pyrolitic catalysts. The composite materials have been fully characterized from a textural and chemical point of view. The proportion of carbon nanofibers and the final content of carbon phases depend on the used pyrolitic metal with Ni being the most active pyrolitic catalysts. The composites show the electro-catalyst activity in the CO 2 reduction to hydrocarbons, favoring all the formation of C1 to C4 hydrocarbons. The tendency of this activity is in accordance with the apparent faradaic efficiencies and the linear sweep voltammetries. The cobalt-based composite shows high selectivity to C3 hydrocarbons within this group of compounds.

From Polyethylene to Highly Graphitic and Magnetic Carbon Spheres Nanocomposites: Carbonization under Pressure

“…The spherical shape of these materials could be attributed to the generated pressure during the pyrolysis process. This statement is based on our previous studies related to plastic waste pyrolyzed into an open reactor, where the presence of carbon microspheres was not found [18].…”

“…During the last few decades, governments and companies have been making a great effort to improve the current environmental situation. In the research field, one of the strategies involves recycling wastes to obtain advanced materials [17,18,19]. On this subject, the world plastic production almost reached 350 million tonnes in 2017.…”

From CO2 to Value-Added Products: A Review about Carbon-Based Materials for Electro-Chemical CO2 Conversion

“…It is mentioned in previous research that when doping carbon gels with metal nanoparticles, some percentage was not accessible to the reactants [209,211]. In that sense, Castelo-Quibén and co-workers [212] synthesized Ni-based catalysts consisting of isolated mesoporous nanospheres doped with nanotubes (CNT) or nanohorns (CNH) by inverse emulsion polymerization of resorcinol and formaldehyde in presence of surfactants. The presence of mesopores allows the electrolyte to penetrate inside the carbon spheres reaching better accessibility to the active sites, while the nanostructured doping materials (CNT and CNH) reduce resistance by increasing electrical conductivity.…”

“…The catalysts doped with Ni nanoparticles by the first method do not improve the catalytic activity with respect to their supports (without doping) due to the Ni-particles embedding on the carbon matrix and thus the inaccessibility of reactants to the active sites, while the Ni-impregnated catalysts by the second method improve the activity to produce hydrocarbons, since it allowed place nickel on the surface of the nanospheres leaving the active sites exposed. As a green-alternative to carbon gels, Castelo-Quibén and co-workers [212] proposed using plastic waste for the manufacture of carbon-based materials, which serve as supports to obtain low-cost electrocatalysts for the CO 2 electroreduction to hydrocarbons. The result was the obtaining of materials with overlapping carbon particles, in which hollow carbon nanofibers emerged and the Fe, Co, and Ni metal particles were located.…”

Catalytic, Photocatalytic, and Electrocatalytic Processes for the Valorization of CO2

“…An example of the electro-reduction of CO 2 was proposed by Castelo-Quibén et al [29], obtaining C1 to C4 hydrocarbons, as an efficient strategy for C-C coupling. The electroactive materials were composite metal-carbon-carbon nanofibers synthesized using urban plastic residues through catalytic pyrolysis.…”