Significantly enhanced catalytic performance of Pd nanocatalyst on AlOOH featuring abundant solid surface frustrated Lewis pair for improved hydrogen activation

Abstract

The catalytic performance of a catalyst is significantly influenced by its ability to activate hydrogen. Constructing frustrated Lewis pairs (FLPs) with the capacity for hydrogen dissociation on non-reducible supports remains a formidable challenge. Herein, we employed a straightforward method to synthesize a layered AlOOH featuring abundant OH defects suitable for constructing solid surface frustrated Lewis pair (ssFLP). The results indicated that the AlOOH-80 (synthesized at 80 °C) possessed an appropriate crystalline structure conducive to generating numerous OH defects, which facilitated the formation of ssFLP. This was further evidenced by the minimal water adsorption in the AlOOH-80, inversely correlated with the quantity of defects in the catalyst. As expected, the Pd loaded onto AlOOH (Pd/AlOOH-80) exhibited excellent catalytic activity in hydrogenation reactions, attributed to abundant defects available for constructing ssFLP. Remarkably, the Pd/AlOOH-80 catalyst, with larger-sized Pd nanoparticles, displayed notably superior activity compared to commercial Pd/Al₂O₃ and Pd/C, both featuring smaller-sized Pd nanoparticles. Evidently, under the influence of ssFLP, the size effect of Pd nanoparticles did not dominate, highlighting the pivotal role of ssFLP in enhancing catalytic performance. This catalyst also exhibited exceptionally high stability, indicating its potential for industrial applications.