Sub‐2 Nm Palladium Phosphide: A Highly Active and Selective Catalyst for the Hydrogenation of Furfural to Furfuryl Alcohol

Phosphidation offers a promising approach to tailor noble metal properties for high catalytic selectivity, yet achieving highly dispersed noble metal phosphides with efficient atom utilization remains challenging. Herein, we report the controlled synthesis of ultrafine palladium phosphides (PdxPy) with sub-2 nm dimensions via a defect-assisted anchoring strategy, using defect-rich TiO2-supported Pd (Pd/d-TiO2) as the phosphidation precursor. The strong anchoring effect of d-TiO2 defects effectively mitigates the aggregation of PdxPy during phosphidation, yielding uniformly dispersed PdxPy nanoparticles with an average size of 1.68 nm. The resulting PdxPy/d-TiO2 exhibits exceptional performance for the selective hydrogenation of furfural to furfuryl alcohol, achieving 97.5% selectivity and a turnover frequency (TOF) of 833.8 h-1. This significantly outperforms the unphosphated Pd/d-TiO2 (54.7% selectivity and TOF of 220.6 h-1) and large-sized PdxPy (5.18 nm) on pristine TiO2 (95.3% selectivity and TOF of 347.4 h-1). The enhanced performance of PdxPy/d-TiO2 is attributed to the high Pd atom utilization and phosphidation-induced generation of isolated Pd sites that minimize the side reactions by modulating furfural adsorption and spillover H2 formation. Our findings provide a novel and effective approach for the controllable synthesis of ultrafine noble metal phosphides by leveraging the defect-anchoring effect, advancing both atomic economy and selective hydrogenation catalysis.