(319c) Unlocking Hydrogen Carrier Potential: Integrated Mechanistic Studies and Surrogate Modeling

Formate (HCOO⁻) stands out as a promising liquid organic hydrogen carrier (LOHC), offering potentially efficient storage and release of hydrogen. Our investigations on Pd(111) elucidate key mechanistic steps in formate dehydrogenation and uncover how formate accumulation accelerates catalyst deactivation by blocking active sites and elevating activation barriers. Comparative studies involving PdO and PdH phases reveal that both oxidation and reduction conditions influence stability and dehydrogenation performance, especially within a potential range of -0.4 to 0.2 V vs. SHE (Figure 1). Concurrently, we tackle the broader challenge of catalyst degradation in LOHC systems, integrating multiscale modeling and experimental data to identify and mitigate chemical and physical pathways responsible for performance decline. By systematically characterizing these degradation modes, we seek to inform more durable catalyst designs and operating conditions.

Building on these mechanistic insights, we extend our framework to compare hydride- and carrier-based strategies for hydrogen production, particularly focusing on electrochemical toluene hydrogenation. Using a bottom-up approach grounded in literature-derived Tafel data (activity, selectivity, and catalyst composition/loading), we employ a simplified (0D) electrolyzer model to identify governing parameters without immediate reliance on complex simulations. A subsequent reverse-design phase—coupled with surrogate modeling and targeted COMSOL-based sensitivity analyses—highlights key trade-offs between cost, activity, and stability, ultimately guiding the optimization of catalyst formulations. By integrating mechanistic, data-driven, and modeling perspectives, our work delivers actionable guidelines for enhancing catalyst performance and longevity across multiple hydrogen carrier pathways.

Figure 1. A heatmap for the variation of dehydrogenation rate (sec^-1) against the operational choices of temperature and the electrode potential. the thermal mode of operation is denoted by the vertical red line (at the PZC of Pd), while the room temperature electrochemical route is shown via the horizontal blue line.