(569d) DFT Investigation of Intermetallic Alloys As Electrocatalysts

Electrocatalysis offers a sustainable pathway by enabling chemical transformations to be driven by renewable electricity at ambient conditions. Intermetallic alloys are promising electrocatalysts due to their ability to independently tune both surface reactivity and the work function through alloying [1]. However, fundamental understanding regarding both the driving force and composition across different late and post-transition metal alloys for electrocatalysts is in its infancy. Due to the complex nature and challenging electrochemical synthesis of intermetallic compounds, it is difficult to obtain a clear understanding of the precise molecular arrangement on their surfaces from experimental characterization alone.

Herein, we utilized a combined DFT-ML approach to construct plausible models of the PdGe intermetallic alloy and explain the origin of its electrocatalytic reactivity. We focus on the PdGe intermetallic alloy, observing that this alloy exhibits higher activity towards ORR/CO oxidation and greater oxidative stability relative to monometallic Pd. We enumerated different active sites for key intermediates (OH* and CO*) across these different surfaces to probe the bifunctional nature of these alloys using GASpy and DFT methods. We then compared the stability and activity of these alloys relative to monometallic Pd. This approach allows us to identify and optimize the specific functionalities of active sites within the intermetallic framework, leading to improved catalytic performance and insights into the mechanistic pathways of electrocatalytic processes.

[1] Clark EL, Nielsen R, Sørensen JE, Needham JL, Seger B, Chorkendorff I. Tuning Surface Reactivity and Electric Field Strength via Intermetallic Alloying. ACS Energy Lett. 2023 Sep 27;8(10):4414-4420. doi: 10.1021/acsenergylett.3c01639. PMID: 37854044; PMCID: PMC10580307.