Continuous Phase Regulation of a Pd–Te Hexagonal Nanoplate Library

Abstract

Phase regulation of noble metal-based nanomaterials provides a promising strategy for boosting the catalytic performance. However, realizing the continuous phase modulation in two-dimensional structures and unveiling the relevant structure-performance relationship remain significant challenges. In this work, we present the first example of continuous phase modulation in a library of Pd–Te hexagonal nanoplates (HNPs) from cubic-phase Pd 4 Te, rhombohedral-phase Pd 20 Te 7, rhombohedral-phase Pd 8 Te 3, and hexagonal-phase PdTe to hexagonal-phase PdTe 2 . Notably, the continuous phase regulation of the well-defined Pd–Te HNPs enables the successful modulation of the distance between adjacent Pd active sites, triggering an exciting way for tuning the relevant catalytic reactions intrinsically. The proof-of-concept oxygen reduction reaction (ORR) experiment shows a Pd–Pd distance-dependent ORR performance, where the hexagonal-phase PdTe HNPs present the best electrochemical performance in ORR (mass activity and specific activity of 1.02 A mg –1 Pd and 1.83 mA cm –2 Pd at 0.9 V vs RHE). Theoretical investigation reveals that the increased Pd–Pd distance relates to the weak *OH adsorption over Pd–Te HNPs, thus contributing to the remarkable ORR activity of PdTe HNPs. This work advances the phase-controlled synthesis of noble metal-based nanostructures, which gives huge impetus to the design of high-efficiency nanomaterials for diverse applications.