Computational Search for Multimetallic Alloys to Replace Precious Metal Catalysts for Formate Dehydrogenation

Author

Ahmad Arshadi, Louisiana State University and Agricultural and Mechanical CollegeFollow

Semester of Graduation

Summer 2025

Degree

Master of Chemical Engineering (MChE)

Department

Cain Department of Chemical Engineering

Document Type

Thesis

Abstract

Precious noble metal catalysts are widely used in the chemical industry because of their unique surface reactivity and selectivity. For certain reactions, however, the high cost of these catalysts can hinder their economic feasibility. For instance, formate-salt dehydrogenation offers a promising, reversible, on‑demand H₂ storage and transport method under mild conditions. This approach can potentially link large‑scale H₂ production with end‑use applications. The most active catalysts for formate salt dehydrogenation are Pd and Pd‑based alloys such as AuPd and AgPd nanoparticles. Yet these materials remain expensive, prone to deactivation, and still fall short in activity. Unless a less costly, more active catalyst can be designed, formate salts will struggle to achieve commercial viability as hydrogen carriers.

To address this, we have performed a theoretical search for multimetallic disordered alloys that can mimic the catalytic performance of AuPd. To begin with, we hypothesize that the surface reactivity of the catalyst is controlled primarily by the bulk electronic structure. Therefore, we combined a Genetic Algorithm (GA) with electronic structure calculations based on the Korringa–Kohn–Rostoker Coherent Potential Approximation (KKR‑CPA) to identify compositionally random alloys whose density of states replicates that of AuPd. As a result, three ternary candidates were identified: Ag_0.40Ni_0.20Pd_0.40, Ag_0.40Cu_0.30Ni_0.30, and Ag_0.40Cu_0.20Pd_0.40. Since no finite supercell can uniquely represent a disordered alloy phase, we leveraged the Virtual Crystal Approximation (VCA) approach to perform calculations to investigate the surface reactivity of these alloys. The adsorption energy of atomic hydrogen is chosen to illustrate this approach, both for its simplicity and for the strong relevance of H in renewable energy applications including formate dehydrogenation. H adsorption energies are computed on adsorption sites with all possible compositions of its first coordination shell (i.e. the nearest-neighbor atoms directly surrounding the site) on the close-packed facet of each ternary alloy. Then, Gaussian distributions were applied to approximate the distributions of adsorption energies as a result of completely random atomic arrangements in the surface. The results suggest that the selected alloys hold promise for replicating the surface reactivity of AuPd. Pending future experimental validation, this approach could prove effective in guiding the design of cost‑effective, high‑performance catalysts for a variety of applications, reducing reliance on scarce noble metals.

Date

7-2-2025

Recommended Citation

Arshadi, Ahmad, "Computational Search for Multimetallic Alloys to Replace Precious Metal Catalysts for Formate Dehydrogenation" (2025). LSU Master's Theses. 6174.
https://repository.lsu.edu/gradschool_theses/6174

Committee Chair

Xu, Ye.