Visualizing Porous Particle Fabrication With Sacrificial Supports

Engineered porous particles have a wide range of applications, such as gas sensing and catalyst supports.  Porous support materials of tungsten/alumina are fabricated via atomic layer deposition (ALD) on sacrificial templates of hydroxylated methacylic polymer.  Conformal films are formed on the sacrificial material by two separate sequential self-limiting surface half reactions of Al(CH₃)₃ and H₂O for alumina and similarly for other materials.  Reactions were performed at temperatures below material phase transition temperatures; once the desired film thickness was achieved the polymer template was volatilized at temperatures above 400°C. 

In this study, controlled physical characteristics of particles are explored.  Physical properties of particles are characterized before and after material deposition and after removal of the sacrificial polymer.  Properties include particle size, surface area, pore volume, pore size and porosity as well as chemical composition are presented.  Internal structure of the porous particles as well as particle packing is explored via 3D X-ray tomography.