Synthesis of Core – Shell Structures of Catalytic Nanoparticles
Nisha Shukla, ICES
The key challenges in heterogeneous catalysis are improvement of activity, selectivity and catalyst stability at operating conditions. One of the primary impediments to improving selectivity is the fact the traditional methods of catalyst preparation generate materials with an inhomogeneous distribution of catalyst particle sizes and shapes and thus, a heterogeneous distribution of active sites. Modern chemical synthesis techniques offer an opportunity to overcome some of these traditional challenges.
The objective of the proposed work is to utilize these novel methods to
synthesize metal nanoparticles with precise control over size and
shape, and thus prepare catalysts with highly uniform distributions of
active sites. The proposed effort will synthesize Pt, Pd, Rh and
PtxPdyRh1-x-y nanoparticle catalysts, characterize their size and shape
distributions, and investigate their catalytic reactivity and stability
for simple, but technologically relevant, probe reactions such as CO
and hydrogen oxidation. In order to improve catalyst stability, these
nanoparticles will furthermore be coated with protective silica
shells. The shell thickness and porosity will be controlled to attain
maximum thermal stability with minimal loss of reactivity. The
outcomes of the proposed work will include a set of highly optimized
catalyst materials, a range of methodologies for the preparation of
tailored catalysts, and an improved understanding for how size and
shape of nanoparticles affect activity and selectivity of a catalyst.