Preparation of graphene oxide supported Ni/Pt nanoparticle catalysts via wet chemistry for biomass application

The urgent need for sustainable energy sources has driven significant interest in biomass as a renewable alternative to fossil fuels. Biomass conversion presents technological challenges due to its complex organic composition, requiring efficient and environmentally friendly catalytic processes. This project focuses on developing advanced catalytic systems using nickel (Ni) and platinum (Pt) nanoparticles supported on graphene and cellulose loofah sponge (CLS) for biomass conversion. Graphene’s high surface area and electronic conductivity, measured at 1.61 ± 0.57 mS/cm after reduction from graphene oxide, combined with the biodegradable nature of CLS, offer promising support structures for green chemistry.

The synthesis of these catalysts was carried out using both conventional hydrothermal and microwave-assisted hydrothermal methods. Hydrothermal synthesis produced acidular nickel nanoparticles with a length-to-width aspect ratio between 1.0 and 4.0 and platinum nanoparticles with an average diameter of 180 nm, demonstrating excellent nanoparticle size control and dispersion. Meanwhile, microwave-assisted hydrothermal synthesis significantly reduced reaction time, achieving nanoparticle characteristics comparable to conventional methods within only 10 minutes. Although effective, controlling nanoparticle morphology consistently remained challenging using microwave techniques.

Catalytic performance was evaluated through the catalytic conversion of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP), achieving complete conversion in just 6 minutes, indicating high catalytic efficiency. Energy-dispersive X-ray spectroscopy (EDX) confirmed the purity of synthesized nanoparticles, showing 100 wt% nickel and platinum composition. Additionally, Pt/Ni alloy nanoparticles were explored for their synergistic catalytic effects, though uniform alloy formation proved difficult due to the different reduction potentials of the metals.

Graphene-supported catalysts consistently outperformed CLS-supported systems due to superior electron transfer capabilities, as evidenced by rapid catalytic conversions. Nevertheless, the sustainable and biodegradable nature of CLS continues to position it as an attractive support for environmentally conscious applications. This research advances sustainable catalysis by enhancing nanoparticle synthesis methods, quantitatively assessing catalyst morphology and composition, exploring biodegradable support materials, and providing deeper insights into metal-support interactions that enhance catalytic performance. Future work will focus on optimizing microwave-assisted synthesis parameters, refining control over nanoparticle morphology, and exploring further the potential of Pt/Ni alloys and CLS-based catalysts in industrial-scale applications.