An integral design and synthesis approach to heterogeneous catalysts: Tailoring the surface characteristics and mass and heat transport properties

Abstract

A novel integrated approach to designing and synthesizing heterogeneous catalysts with customized surface characteristics and improved heat and mass transport properties is studied. This unique approach utilizes hydrothermal reactions of aluminum (Al) metal substrates with controlled interfacial chemistry, manipulating the kinetics of aluminum hydroxide crystal growth to develop Al@Al2O3 core–shell metal-ceramic composite micro-architectures. The shapes, spatial orientation, and surface-exposed crystal facets of the porous γ-Al2O3 crystallites of the Al@Al2O3 core–shell are effectively tailored via modulation of the specific charge interaction of the boehmite crystallites with heteroatom ions in the solution. The reaction chemistry and formation mechanism of the Al@Al2O3 core–shell micro-composites with morphologically modulated γ-Al2O3 crystallites are studied in detail, along with their physicochemical and catalytic properties. For the acid-catalyzed ethanol dehydration reaction, the Al@Al2O3 catalysts with tailored morphologies and exposed γ-Al2O3 crystal facets demonstrate the high effectiveness of the integrated design and synthesis approach to heterogeneous catalysts, modulating the intrinsic catalytic activities with enhanced mass and heat transport properties at the same time.