State-of-the-art Nanofabrication in Catalysis

Abstract

We present recent developments in top-down nanofabrication that have found application in catalysis research. To unravel the complexity of catalytic systems, the design and use of models with control of size, morphology, shape and inter-particle distances is a necessity. The study of well-defined and ordered nanoparticles on a support contributes to the understanding of complex phenomena that govern reactions in heterogeneous and electro-catalysis. We review the strengths and limitations of different nanolithography methods such as electron beam lithography (EBL), photolithography, extreme ultraviolet (EUV) lithography and colloidal lithography for the creation of such highly tunable catalytic model systems and their applications in catalysis. Innovative strategies have enabled particle sizes reaching dimensions below 10 nm. It is now possible to create pairs of particles with distance controlled with an extremely high precision in the order of one nanometer. We discuss our approach to study these model systems at the single-particle level using X-ray absorption spectroscopy and show new ways to fabricate arrays of single nanoparticles or nanoparticles in pairs over a large area using EBL and EUV-achromatic Talbot lithography. These advancements have provided new insights into the active sites in metal catalysts and enhanced the understanding of the role of inter-particle interactions and catalyst supports, such as in the phenomenon of hydrogen spillover. We present a perspective on future directions for employing top-down nanofabrication in heterogeneous and electrocatalysis. The rapid development in nanofabrication and characterization methods will continue to have an impact on understanding of complex catalytic processes.

The Extent of Platinum-Induced Hydrogen Spillover on Cerium Dioxide

“…A model was produced using a thin film approach in combination with eBL (Figure 1a). 32 A flat ceria surface with two distinct regions was prepared, where one of the regions was covered by platinum nanostructures and the other was free of platinum. The two regions are part of the same ceria surface.…”

Plasma Generating—Chemical Looping Catalyst Synthesis by Microwave Plasma Shock for Nitrogen Fixation from Air and Hydrogen Production from Water for Agriculture and Energy Technologies in Global Warming Prevention

“…Such attributes of the plasma generating catalysts can be enhanced through binary catalysts which can promote sequential reactions and plasma generation. In this section, we briefly exemplify binary catalyst systems which can further promote catalytic reactions when the rate determining steps require different catalysts in close proximity as described recently [57]. Detailed study of such systems is the subject of another study.…”

The Catalytic Mechanics of Dynamic Surfaces: Stimulating Methods for Promoting Catalytic Resonance

“…The pursuit of “better” catalysts relies on the design philosophy that refined structures will always provide faster and more selective catalysts; − however, this strategy eventually approaches the fundamental limitations on static catalytic sites. The most restrictive catalytic limitation is the Sabatier principle, which posits that optimal catalysts exhibit intermediate surface binding energies to balance the kinetic rates of two or more reaction phenomena including surface reactions, desorption, or adsorption .…”