(583eh) Nanostructured Catalysts for Solar Driven Chemical Transformations | AIChE

(583eh) Nanostructured Catalysts for Solar Driven Chemical Transformations


Christopher, P. - Presenter, University of California, Santa Barbara
Kale, M., University of California, Riverside
Avanesian, T., University of California, Riverside
Matsubu, J. C., University of California, Riverside

In this work, we show two examples where well-defined nanostructured heterogeneous catalytic systems are designed that exploit nanostructuring to enhance the efficiency of solar driven chemical conversion.

The first example is focused on the design of efficient Pt-based heterogeneous photocatalysts for oxidation reactions. Bulk metals exhibit very low efficiency for driving photocatalytic reactions based on the low energy of photon-induced electron excitations and fast charge carrier relaxation due to electron-electron scattering.  Here we show that confining Pt to nanoscales (< 5nm particles) introduces new photon absorption mechanisms that allow for a unique and efficient pathway for photocatalytic transformations without needing a semiconductor absorber. We will show experimental signatures of nanoscale-induced photochemistry and discuss theoretical frameworks that capture salient qualitative characteristics of the process.  

In the second example, we show how we have designed a multifunctional system with two active sites co-localized on the same support for efficient execution of artificial photosynthesis (CO2 + 2H2O --> CH4 + 2O2).  One active site is designed to perform photocatalytic endothermic water splitting and the other is designed to perform thermo-catalytic exothermic CO2 methanation thereby providing a unique pathway to execute artificial photosynthesis through a combined photocatalytic and thermocatalytic reaction pathway.