(363i) Practical Single-Atom Alloy Catalysts Design for Sustainable Chemical Processes

The single-atom alloy (SAA) is a class of heterogeneous catalysts typically consisting of a reactive dopant metal (e.g., Pt, Pd, Ni) heavily diluted by a relatively inert host metal (e.g., Cu, Ag, Au). These catalysts have advantages such as high atom utilization, lower costs compared to monometallic counterparts, and distinct atomic ensembles which selectively drive reactions such as (de)hydrogenations. Owing to their uniform surface structures, promising SAA candidates can be readily identified via combinations of theoretical simulations and surface science studies on well-defined surfaces in ultrahigh vacuum regimes. However, practical catalytic reactions typically use nanoparticles with more complicated structures in reactors operating at elevated pressures. Accounting for these differences is crucial for the rational development of heterogeneous catalysts. Here, I discuss two concepts involved in implementing these alloys: coverage effects and site restructuring. In the thermal decomposition of formic acid over Ni-doped Cu (NiCu), high coverages were suggested to shift the reaction mechanism relative to vacuum surface studies, leading to a dampened performance compared to prediction. Meanwhile, Rh-doped Cu (RhCu) was found to restructure under in situ environment, such that Rh could move towards and away from the surface, resulting in change of catalytic properties. In addition, details on synthesizing SAA materials with highly uniform structures (necessary to gain fundamental insights under catalytic operating conditions) will also be highlighted. With this knowledge, we more effectively evaluate the practicality and feasibility of synthesizing and applying these catalysts in industrially relevant conditions.

Research Interests:

• Catalysts synthesis with lower costs, fewer pollutants and easiness to handle.
• Characterization of materials to identify active sites and necessary structures
• Rational materials and processes designs to connect fundamental science to engineering