Nickel and Iron Catalysts Supported on Cellulose-Based Carbon Aerogels: An Application of Bcfp

Nickel and iron catalysts for biomass pyrolysis were prepared on carbon aerogel (CAG) supports made from cellulose nanofibers. The nanofibers were impregnated with (NH₄)₂SO₄ and subjected to varying heating rates (10 or 20 °C / min), maximum temperatures (900, 1000, or 1100 °C), and residence times (0, 1, 2, or 5 h) under nitrogen gas to yield carbon aerogels (>90% carbon). The CAG featured high thermal resistance, average pore radius of 2-3 nm, and surface areas of up to 809 m² / g; surface areas were much lower for CAG produced at higher temperatures and longer residence times. CAG were also characterized using X-Ray diffraction (XRD) and Fourier Transform Infrared Spectrometry (FTIR). CAG 90 is an abbreviated notation for CAG produced at 900 °C with 0 h residence time and 10 °C / min heating rate. Samples of CAG 90 were impregnated with nickel nitrate or iron acetylacetonate via incipient wetness. They were then dried and reduced to produce 10 wt% nickel and iron catalysts. Biomass catalyzed fast pyrolysis was performed with Eucalyptus globulus and catalyst in a 1:5 mass ratio using a micro pyroprobe coupled to gas chromatography mass spectrometer (py-GCMS). Both catalysts reduced the selectivity for carboxylic acids, furans, and phenols while increasing the selectivity for larger aromatic compounds. The pyrolysis temperature of 500 °C and duration of 6s failed to yield hydrogen, methane, or other non-CO2 gases.