Influence of ultrasound irradiation power on surface design of CaO nanoparticles over secondary carbon-templated meso designed ZSM-5 for biofuel production from vegetable oil

[Display omitted] •Positive role of secondary charcoal template in creating hierarchical ZSM-5.•Promotion effect of ultrasound energy on dispersion of calcium on hierarchical ZSM-5.•Higher density of the strong basic catalytic sites resulted by secondary templating.•Promoting effect of the secondary templating on biofuel production.•Improvement of catalytic activity and stability by increasing sonication power. A series of potential bifunctional basic/acidic CaO over hierarchical ZSM-5 nanocatalysts were synthesized and investigated in biofuel production. Secondary hard templating was applied on the ZSM-5 support by carbonaceous charcoal particles in order to increase the pore size in favour of better diffusion of the large triglyceride molecules. The ultrasound irradiation was also applied with three different powers on impregnation of CaO active phase and its effect on well dispersing the particles was investigated. FESEM images showed high distributed and smaller particles on the surface of highly sonicated catalyst compared to the non-sonicated sample and BET-BJH results confirmed the opening of the pores and therefore size and volume increase by sonication. TPD-CO2 results indicated that both secondary templating and sonication have increased the strong basic sites. The particles were also smaller and less agglomerated due to sonication as observed in TEM images. Catalytic performance tests also confirmed the effective role of secondary charcoal templating on the conversion of oil as well as the positive influence of ultrasound irradiation. Sonicated nanocatalyst was also more stable after five times of reusability tests in transesterification of sunflower oil.