Maximizing Metal-Support Interactions in Pt/Co3O4 Nanocages to Simultaneously Boost Hydrogen Production Activity and Durability

Catalytic hydrolysis of ammonia borane (AB) provides an effective way to generate pure H-2 at ambient temperature for fuel cells. Pt-based catalysts usually exhibit great initial activity toward this reaction but deactivate quickly. Here, we report that the metal-support interactions in Pt/Co3O4 nanocages can simultaneously accelerate the H-2 generation and enhance the catalyst's stability. The Pt/Co3O4 catalyst is made for the first time by embedding Pt clusters (similar to 1.2 nm) in a high-surface-area Co3O4 nanocage to maximize the metal-support interface. The turnover frequency of the Pt/Co3O4 catalyst is about nine times higher than that of commercial Pt/C and outperforms almost all other Pt-based catalysts. X-ray absorption spectroscopy, X-ray photoelectron spectroscopy, in situ spectroscopy, and density functional theory calculations suggest that the Co3O4 nanocages with rich oxygen vacancies facilitate the adsorption and dissociation of H2O to give electropositive H (H delta+), while the in situ embedded Pt clusters can accelerate the formation of electronegative H (H delta-) from AB. Subsequently, the H delta+ and H delta- spill over to the abundant interfacial sites and bond into H-2. In addition to this dual-function synergy effect, the strong metal-support electronic interactions between Co3O4 and Pt benefit the desorption of poisonous B-containing byproducts from Pt sites. This effect together with cluster anchoring leads to a fivefold enhancement in durability compared to commercial Pt/C. The metal-support interactions revealed in this study provide more options for catalyst design toward facile H-2 production from chemical hydrogen storage materials.

Automated summary

The study demonstrates that Pt/Co3O4 nanocage catalyst can accelerate H2 generation and enhance stability through metal-support interactions, with a ninefold higher turnover frequency compared to commercial Pt/C. The catalyst facilitates H2O adsorption and dissociation, H generation, and desorption of toxic byproducts through strong electronic interactions between Co3O4 and Pt. This dual-function synergy effect leads to a significant enhancement in durability.