Grain boundary-rich palladium nanoclusters anchored on ionic liquid-modified Ti3C2Tx nanosheets for efficient methanol and formic acid electrooxidation

A facile, scalable wet-chemical strategy is developed for in-situ Pd nanoclusters anchored on ionic liquid (IL)-modified Ti 3 C 2 T x nanosheets. • IL modification tunes Ti 3 C 2 T x surface charge, improves its stability and antioxidant capacity, and strengthens electrostatic interaction with Pd precursors to form active grain boundaries. • Pd/IL-Ti 3 C 2 T x shows superior FAOR & MOR electrocatalytic performance: high activity, good CO-poisoning resistance and favorable long-term stability. • Theoretical simulations confirm IL - Ti 3 C 2 T x modulates Pd electronic structure, weakens CO adsorption, and enables the enhanced electrocatalytic activity. Both direct formic acid fuel cell (DFAFC) and direct methanol fuel cell (DMFC) with high energy-conversion efficiency have garnered considerable attention against the backdrop of continuously increasing energy demand, while the actual performance largely depends on the catalytic properties of their anode catalysts. In this work, we present a facile and scalable wet-chemical strategy for synthesizing palladium (Pd) nanoclusters in situ anchored on ionic liquid (IL)-modified two-dimensional Ti 3 C 2 T x MXene nanosheets, which are capable to serve as highly efficient anode catalysts for both formic acid and methanol electrooxidation. The incorporation of IL not only effectively tune the surface charge characteristics of Ti 3 C 2 T x nanosheets to enhance their structural stability and antioxidant capacity, but also strengthens the electrostatic interactions between Pd species and substrate to induce the formation of catalytically active grain boundary sites. As a result, the as-obtained Pd/IL-Ti 3 C 2 T x nanostructure exhibits excellent electrocatalytic performance for both formic acid and methanol oxidation, including large electrochemically active surface areas, high mass/specific activities, strong CO resistance, and dependable long-term stability, which far outperform that of conventional Pd catalysts supported on carbon black, carbon nanotubes, reduced graphene oxide, and pristine Ti 3 C 2 T x substrates. Theoretical simulations further confirm that the stable configuration and optimized electronic structure of Pd nanoclusters on Ti 3 C 2 T ₓ weaken their CO adsorption ability relative to Pd nanoparticles; this provides the foundation for their dramatically enhanced and sustainable electrocatalytic performance. A facile and scalable wet-chemical strategy is developed to synthesize Pd nanoclusters in situ anchored on ionic liquid (IL)-modified Ti 3 C 2 T ₓ nanosheets. The IL modification enhances the structural stability and antioxidant capacity of the Ti 3 C 2 T ₓ support while promoting the formation of catalytically active grain boundary sites via strengthened electrostatic interactions. The resulting Pd/IL-Ti 3 C 2 T ₓ hybrid exhibits outstanding electrocatalytic performance for both formic acid and methanol oxidation, including high mass/specific activities, superior CO tolerance, and excellent long-term stability. Theoretical simulations reveal that the optimized electronic structure of Pd nanoclusters weakens CO adsorption, underpinning the enhanced and sustainable performance. Download: Download high-res image (133KB) Download: Download full-size image