Driving formic acid dehydrogenation by dynamic CO2 removal at palladium interfaces

A universal physical-mixing strategy boosts formic acid dehydrogenation over supported Pd catalysts. • Basic zeolites scavenge CO 2 to enhance formic acid dehydrogenation. • Pd@S-1/1.0CsX achieves a hydrogen production rate of 4269 h −1 . • A CO 2 -deficient microenvironment exposes Pd sites and drives hydrogen evolution. Formic acid dehydrogenation (FAD) is an attractive route for hydrogen release in liquid organic hydrogen carrier systems, but its efficiency is often limited by product accumulation at metal active sites. Herein, we report a simple yet highly effective mixing strategy that markedly enhances FAD by integrating zeolite-encaged Pd nanoclusters with basic zeolites. The resulting bifunctional catalytic system combines the intrinsic activity of subnanometric Pd nanoclusters with the CO 2 -scavenging capability of basic zeolites. As a representative example, the Pd@S-1/1.0CsX catalyst achieves a hydrogen production rate of 4269 h −1 , nearly threefold higher than that of Pd@S-1. Mechanistic investigations indicate that the basic zeolite acts as a local CO 2 sink, dynamically promoting the transfer of newly generated CO 2 away from the Pd/liquid interface and thereby maintaining a CO 2 -deficient microenvironment around the active Pd sites. This interfacial CO 2 scavenging suppresses product readsorption and local product inhibition, continuously exposing accessible Pd sites without altering the intrinsic reaction pathway. The generality of this strategy is demonstrated across a broad range of supported Pd catalysts. This work highlights microenvironment engineering as a powerful concept for advancing heterogeneous catalysis beyond conventional active-site-centered design. Zeolite-encaged Pd nanoclusters are physically mixed with basic zeolites to create a bifunctional catalyst for formic acid dehydrogenation. The basic zeolite scavenges CO 2 , generating a CO 2 -deficient microenvironment that continuously exposes Pd active sites, shifting equilibrium toward H 2 evolution and delivering nearly threefold higher H 2 productivity. Download: Download high-res image (106KB) Download: Download full-size image