Subnanometric bimetallic Pt–Pd clusters in zeolites for efficient hydrogen production and selective tandem hydrogenation of nitroarenes

The solvolysis of ammonia borane (AB) and the hydrogenation of nitroarenes represent significant reactions for hydrogen generation and value-added chemical synthesis. The strategic engineering of the catalysts is imperative for surmounting obstacles associated with their stability and catalytic efficiency. In this work, subnanometric bimetallic Pt–Pd clusters were encapsulated within silicalite-1 (S-1) zeolites through a ligand-protected in-situ hydrothermal synthesis method. The synergetic effect of bimetallic composition and zeolite confinement markedly enhances the catalytic performance of representative Pt_0.5 Pd_0.5@S-1-H catalyst, affording exceptional turnover frequency (TOF) values of 1,043 and 573 mol_H2 mol_metal⁻¹ min⁻¹ for AB hydrolysis and methanolysis at ambient conditions, respectively, surpassing most of the state-of-the-art Pt-based catalysts. Kinetic and isotopic experiments reveal that the bimetallic catalytic system remarkably boosts the O–H cleavage of water, thereby facilitating the H₂ production from AB hydrolysis. Remarkably, a conspicuous synergistic effect is demonstrated in the shape-selective tandem hydrogenation of nitroarenes, with the bimetallic catalyst facilitating both AB hydrolysis and nitroarene hydrogenation, giving a high TOF value of 1,260 h⁻¹ under atmospheric pressure. This study not only demonstrates the effectiveness of bimetallic nanocatalysts encapsulated in zeolites for hydrogen production from chemical hydrogen storage materials, but also paves the way for the design of catalysts with multifunctional active sites capable of synergistically promoting tandem catalytic processes.