Multimodal optimization of synergistic aluminum/nickel catalytic pyrolysis for enhanced hydrogen production from tobacco straw

Abstract

The urgent challenge of greenhouse gas emissions and pollution caused by fossil fuels necessitates the development of sustainable alternatives such as biomass pyrolysis. To enhance the green H₂ production, a fluidized bed is developed for tobacco straw pyrolysis, and combined experimental and numerical investigations are conducted to utilize high-cellulose agricultural waste and assess pyrolysis performance. Effects of catalyst composition (Al/Ni ratio) and operating conditions on H₂ production are analyzed. The results indicate that the Al/Ni bimetallic catalyst significantly outperforms monometallic systems, boosting H₂ yield by 5 % to 30.84 vol% at 973 K via intermetallic electron transfer. Additionally, particle size significantly affects pyrolysis, balancing reaction kinetics and mass transfer efficiency. Furthermore, multimodal characterizations from TGA, FT-IR, XPS, XRD and Raman confirm that the Al/Ni successful doping in the pyrolyzed carbon matrix, structurally modulating the carbon skeleton to promote H₂ production. The optimum conditions (Tₚ=973 K, mᵢ=6 L/min, mb=1.5 L/min, 70 mesh particles) are identified via response surface analysis and experimentally validated. This research provides actionable process settings to enhance H₂ production efficiency from tobacco straw pyrolysis and a theoretical basis for bimetallic co-pyrolysis modulation.