Synthesis and characterization of supported bimetallic overlayer catalysts

Directed deposition was used to synthesize alumina-supported bimetallic overlayer Pd on Re (Re@Pd) and Pt on Ni (Ni@Pt) catalysts. The directed deposition technique combines the use of inhibitors and a surface reaction to produce the desired overlayer structure. Re@Pd catalysts showed decreased hydrogen heat of adsorption compared to Pd or Re monometallic catalysts as predicted by computational studies. The directed deposition technique was used to synthesize alumina-supported bimetallic overlayer Pd on Re (Re@Pd) and Pt on Ni (Ni@Pt) catalysts. Computational and single crystal studies have predicted unique adsorption properties for similar overlayer type catalysts compared to the monometallic catalysts. The directed deposition technique combines the use of inhibitors and a surface reaction to produce the desired overlayer structure. The Re@Pd and Ni@Pt catalysts were characterized using hydrogen chemisorption, transmission election microscopy (TEM), and energy dispersive spectroscopy (EDS) to correlate properties with synthesis conditions. H 2 chemisorption indicated the proper synthesis conditions to deposit the overlayer metal on the base metal catalyst particle as desired. When a surface deposition inhibitor was not used, evidence for the formation of isolated particles of the overlayer metal was detected. Re@Pd catalysts showed decreased hydrogen heat of adsorption compared to Pd or Re monometallic catalysts as predicted by the literature. Ni@Pt catalysts demonstrated intermediate H 2 heat of adsorption compared to Pt and Ni. TEM/EDS were used to demonstrate that the overlayer metal was associated with the base metal particles as desired.