TY - JOUR
T1 - Shape-selective sieving layers on an oxide catalyst surface
AU - Canlas, Christian P.
AU - Lu, Junling
AU - Ray, Natalie A.
AU - Grosso-Giordano, Nicolas A.
AU - Lee, Sungsik
AU - Elam, Jeffrey W.
AU - Winans, Randall E.
AU - Van Duyne, Richard P.
AU - Stair, Peter C.
AU - Notestein, Justin M.
PY - 2012/12/1
Y1 - 2012/12/1
N2 - New porous materials such as zeolites, metal-organic frameworks and mesostructured oxides are of immense practical utility for gas storage, separations and heterogeneous catalysis. Their extended pore structures enable selective uptake of molecules or can modify the product selectivity (regioselectivity or enantioselectivity) of catalyst sites contained within. However, diffusion within pores can be problematic for biomass and fine chemicals, and not all catalyst classes can be readily synthesized with pores of the correct dimensions. Here, we present a novel approach that adds reactant selectivity to existing, non-porous oxide catalysts by first grafting the catalyst particles with single-molecule sacrificial templates, then partially overcoating the catalyst with a second oxide through atomic layer deposition. This technique is used to create sieving layers of Al 2O 3 (thickness, 0.4-0.7 nm) with 'nanocavities' (<2 nm in diameter) on a TiO 2 photocatalyst. The additional layers result in selectivity (up to 9:1) towards less hindered reactants in otherwise unselective, competitive photocatalytic oxidations and transfer hydrogenations.
AB - New porous materials such as zeolites, metal-organic frameworks and mesostructured oxides are of immense practical utility for gas storage, separations and heterogeneous catalysis. Their extended pore structures enable selective uptake of molecules or can modify the product selectivity (regioselectivity or enantioselectivity) of catalyst sites contained within. However, diffusion within pores can be problematic for biomass and fine chemicals, and not all catalyst classes can be readily synthesized with pores of the correct dimensions. Here, we present a novel approach that adds reactant selectivity to existing, non-porous oxide catalysts by first grafting the catalyst particles with single-molecule sacrificial templates, then partially overcoating the catalyst with a second oxide through atomic layer deposition. This technique is used to create sieving layers of Al 2O 3 (thickness, 0.4-0.7 nm) with 'nanocavities' (<2 nm in diameter) on a TiO 2 photocatalyst. The additional layers result in selectivity (up to 9:1) towards less hindered reactants in otherwise unselective, competitive photocatalytic oxidations and transfer hydrogenations.
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U2 - 10.1038/nchem.1477
DO - 10.1038/nchem.1477
M3 - Article
C2 - 23174984
AN - SCOPUS:84870218709
VL - 4
SP - 1030
EP - 1036
JO - Nature Chemistry
JF - Nature Chemistry
SN - 1755-4330
IS - 12
ER -