Enhanced Catalyst Durability for Bio-Based Adipic Acid Production by Atomic Layer Deposition

Atomic layer deposition (ALD) improves the durability of metal catalysts using nanoscale metal oxide coatings. However, targeted coating strategies and economic models are lacking for process-specific deactivation challenges that account for implications at scale. Herein, we apply Al2O3 ALD to Pd/TiO2 to increase durability during hydrogenation of muconic acid, a bio-based platform chemical, to adipic acid. Initial coating development and characterization are performed on the milligram scale using stop-flow ALD. Subsequently, ALD coating scale is increased by 3 orders of magnitude using fluidized bed ALD. Activity, leaching resistance, and thermal stability are evaluated at each synthesis scale. ALD-coated catalysts retain up to 2-fold greater muconic acid hydrogenation activity and undergo significantly less physical restructuring than uncoated Pd/TiO2 after high-temperature treatments, while reducing Pd leaching by over 4-fold. Techno-economic analysis for an adipic acid biorefinery supports increased ALD material costs through catalyst lifetime extension, underscoring the potential viability of this technology. [Display omitted] •ALD increases Pd/TiO2 leaching and thermal stability for bio-based adipic acid•ALD dramatically retards anatase to rutile transformation for TiO2 support•Catalyst stability retained when scaling ALD coatings by 3 orders of magnitude•Techno-economic analysis shows value of extended catalyst lifetime despite ALD cost Emerging biomass conversion processes often require challenging reaction environments that shorten catalyst lifetimes through premature deactivation. Sufficient catalyst lifetimes are critical for advancing biomass conversion toward industrial scale. Here, we demonstrate that thin metal oxide coatings by atomic layer deposition (ALD) improve catalyst leaching stability in acidic media and enhance thermal stability of both the active metal sites and support. Techno-economic analysis highlights the potential of Al2O3 ALD coatings to reduce bio-based chemical production costs at the 70 kiloton per year scale through increased catalyst lifetimes and sufficient retained activity. The potential for economical ALD coatings for catalyst durability has implications beyond biomass conversion, including other renewable energy and chemical processes facing catalyst stability challenges. Biomass conversion processes often require challenging reaction environments that shorten catalyst lifetimes through deactivation. This work dem