The performance of heterogeneous catalysts in practice is often governed by thermal and mass transport limitation, as the overall rate of catalytic reactions are coupled with intrinsic surface reaction kinetics, heat transport, and fluid dynamics of reactants/products through the catalysts. In this work, we will present unique Al-based metal-ceramic composite catalysts with core-shell microarchitecture that can provide superior catalytic properties to conventional heterogeneous catalysts for chemical reactions that require intensive thermal and mass flux such as hydrogen production fuel processing for fuel cells. Simple hydrothermal treatment of Al particles in solution of metal ions at elevated temperatures afford self-construction of the core-shell composite microstructure with various surface compositions, morphologies, and physicochemical properties which can deliver enhanced catalytic performance for the reactions. Extensive experimental and theoretical investigation with period 3−6 metal elements (Na+, Ca2+, Sr2+, Ba2+, K+, Fe3+, Cu2+, Zn2+, Ni2+, Co2+, Mn2+, and Mg2+) at various metal concentrations and temperatures have revealed that the heterogeneous self-construction of spinel-MeAl2O4@Al primarily depends on two intrinsic properties of the additive metal ions: (i) thermodynamic stability constant of the metal hydroxide complex and (ii) size of the metal ion. The spinel-MeAl2O4@Al microstructures formed with hetero metal ions (Me = Zn2+, Ni2+, Co2+, Mn2+, and Mg2+) of (i) moderate rates of the hydroxide formation with compatible kinetics to the hydrolysis of aluminum on the Al surface and (ii) small size of additive metal ions enough for diffusion through the shell layer. The performance and effects of these unique metal-ceramic composite catalysts will be demonstrated with catalytic fuel reforming reactions for renewable hydrogen production at high space velocity conditions.

Metal-ceramic core-shell microstructure catalysts: Applications in renewable hydrogen production

254th National Meeting (2017)

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