Aerogel Catalyst Support: Pore Diffusion & Effectiveness Factor

Aerogels make exceptional catalyst supports because their sol-gel-derived network of nanoscale struts packs hundreds of square metres of internal surface into every gram, giving dispersed metal nanoparticles an enormous area to sit on. That surface is only useful if reactant molecules can actually reach it — and in pores a few tens of nanometres wide, gas transport is dominated by Knudsen diffusion (wall collisions), not ordinary bulk diffusion. This simulator renders a spherical aerogel catalyst pellet as a cloud of instanced strut/site nodes and solves the classic diffusion–reaction problem for a first-order reaction to get the real internal concentration profile C(r), the Thiele modulus φ, and the effectiveness factor η — the fraction of that expensive high-surface-area interior that is actually doing catalytic work at any given pore size, pellet size and reaction rate.