Tailoring catalysts with atomic level control over active sites and composite structures is of great importance for advanced catalysis. This review focuses on the recent development of area selective atomic layer deposition (ALD) methods in composite catalysts design and synthesis. By adjusting and optimizing the area selective ALD processes, several catalytic structures are developed, including core shell structures, discontinuous overcoating structures, and embedded structures. The detailed synthesis strategies for these designed structures are reviewed, where the related selective approaches are highlighted and analyzed. In addition, the catalytic performance of such structures, including activity, selectivity, and stability, is discussed. Finally, a summary and outlook of area selective ALD for catalysts synthesis and applications is given.
We report an atomic scale controllable synthesis of Pd/Pt core shell nanoparticles (NPs) via area-selective atomic layer deposition (ALD) on a modified surface. The method involves utilizing octadecyltrichlorosilane (ODTS) self-assembled monolayers (SAMs) to modify the surface. Take the usage of pinholes on SAMs as active sites for the initial core nucleation and subsequent selective deposition of the second metal as the shell layer. Since new nucleation sites can be effectively blocked by surface ODTS SAMs in the second deposition stage, we demonstrate the successful growth of Pd/Pt and Pt/Pd NPs with uniform core shell structures and narrow size distribution. The size, shell thickness and composition of the NPs can be controlled precisely by varying the ALD cycles. Such core shell structures can be realized by using regular ALD recipes without special adjustment. This SAMs assisted area-selective ALD method of core shell structure fabrication greatly expands the applicability of ALD in fabricating novel structures and can be readily applied to the growth of NPs with other compositions.
9 January 2017 in Angewandte Chemie International Edition