The efficient use of biowaste to decrease environmental pollution is vital for the long-term sustainability of the planet. A study published in the Journal of Environmental Chemical Engineering used waste grapefruit peels to synthesize multipurpose nickel nanoparticles ingrained in nitrogen graphene-like carbon nanomaterials (Nix @ NGC) with excellent electromagnetic characteristics.
Study: Construction of Nickel Nanoparticles Embedded in Nitrogen Self-doped Graphene-like Carbon Derived from Waste Grapefruit Peel for Multifunctional OER, HER, and Magnetism Investigations. Image Credit: Julia Manga/Shutterstock.com
Owing to its intrinsic characteristics, such as low cost, reusability, and low toxicity, biomass has been regarded as one of the potential alternatives for producing multifunctional materials in recent years.
However, a considerable volume of biowaste from the agriculture, paper, and furniture industry is not properly managed. Some of it is even burnt to produce harmful carbon dioxide and carbon monoxide gases, leading to environmental pollution.
Applications of Biomass Derived Carbon-Materials
Biomass-derived carbon materials have shown potential for application in sophisticated sensors as well as sustainable energy production and storage due to their remarkable electromagnetic properties.
The inherent permeable structure of biomass may be efficiently conserved in carbon materials, which is beneficial to the conductivity of the electrolytes.
As well as this, their large specific surface area increases the response rate and enhances the overall performance of the material.
Carbonization can be used to change the electronic configuration and charge density of biomass by doping the carbon skeleton with heteroatoms, such as nitrogen or phosphorus, which are naturally present in biomass.
However, the effective use of biomass-derived carbon materials in water electrolysis is problematic due to a lack of effectively active catalytic regions.
Combining carbon nanomaterials like graphene and CNTs with metallic nanoparticles is an effective technique to tackle this issue and expand their applications in water electrolysis processes like hydrogen evolution reactions (HER) and oxygen evolution reactions (OER).
Instead of graphene or CNTs, biomass-derived carbon materials can also be combined with metallic (Ni) nanoparticles to not only increase HER and OER applications but also reduce biowaste.
A Novel Technique of Nix @ NGC synthesis using Grapefruit Peels
In this study, the researchers describe a straightforward impregnation-carbonization technique for creating a series of nickel nanoparticles implanted in nitrogen-doped carbon nanomaterials (Nix @NGC) for multipurpose OER, HER, and magnetic research.
Discarded grapefruit skin was used as a carbon source during the synthesis, whereas nickel nitrate hexahydrate was used as a nickel source.
Before using grapefruit skins, the heavy outer layer was scraped with a blade and rinsed three times to eliminate any contaminants.
The grapefruit peels were then cured at 80 degrees Celsius for 10 hours before being crushed using a blender. Then, 3.5g of newly produced skins were dissolved in 8 mmol of nitric acid to generate three separate Nix @NGC samples.
Electrocatalytic and Magnetic Applications
The researchers discovered that Nix @NGC nanocomposites produced from discarded grapefruit peels had remarkable OER, HER, and magnetic properties.
The outstanding electrocatalytic performance of Nix @NGC can be associated with the formation of Ni, which provides a large number of active catalytic spots, as well as the direct contact between Ni nanostructures and conductive nitrogen-doped carbon, ensuring proper charge transport and structural adhesion.
The enhanced magnetic performance of the sample relates to the fact that increasing the temperature and Ni quantity tends to lower the Hc of the sample, suggesting its likely change from a ferromagnetic to a superparamagnetic material.
It was revealed that NGC nanocomposites containing 20% nickel provided optimal performance for OER, HER, and applications.
Carbonization, heat, and the quantity of nickel can be used to control the electrocatalytic and magnetic characteristics of the material.
While the biomass organic matter was carbonized, NGC nanocomposites reduced active nickel ions (Ni2+) to Ni to provide a catalytic component in the process. The OER and HER conductance of the optimal nanocomposite were 360 mV and 165 mV in potassium oxide solution.
Significance of the Study
In this research, multipurpose nanomaterials with nitrogen doping and nickel deposition were effectively produced using a facile impregnation-carbonization technique that employed grapefruit skins as carbon sources and nickel nitrate hexahydrate as carbon sources a nickel source.
The electrocatalytic and magnetic characteristics of the Ni @NGC material that was produced were remarkable. In the future, this unique approach may be used for the eco-friendly synthesis of versatile nanocomposites.
Continue reading: An Overview of the Synthesis and Application of Green Nanoparticles.
He, F. et al. (2021) Construction of nickel nanoparticles embedded in nitrogen self-doped graphene-like carbon derived from waste grapefruit peel for multifunctional OER, HER, and magnetism investigations. Journal of Environmental Chemical Engineering, 9(6), 106894. Available at: https://www.sciencedirect.com/science/article/pii/S2213343721018716