Designable Multiphase Nanocrystals Based on Phase Rearrangement

Phase engineering is a significant means of effectively enhancing catalytic performance. However, achieving continuous and precise phase control in intermetallic compounds remains a challenge, which has hindered the development of phase-dependent catalysis. In this work, we demonstrate continuous phase regulation and unveil the crucial role of phase rearrangement in the selective construction of nanocrystals. Through a mechanistic investigation, we uncovered a phase-dependent behavior governing the selective phase transformation during phase rearrangement. When a Pd-rich (Pd₂₀Te₇, the ratios of Pd/Te > 1) template was used, Pd₂₀Te₇ rearranged into PdTe. The Te vacancies generated in this process were occupied by Pb atoms, leading to the formation of a Pd-Pb alloy. Conversely, Te-rich template (PdTe₂, the ratios of Pd/Te < 1) rearranged to PdTe, with the resulting Pd vacancies being occupied by Pb atoms to form a Pb-Te alloy. The customized interface in PdTe-PbTe significantly enhanced its formic acid oxidation reaction (FAOR) activity. The catalyst achieved a mass activity of 4.17 A mg_Pd^-1 and a specific activity of 9.12 mA cm^-2, surpassing commercial Pd/C by factors of 16.68 and 12.67, respectively. This work establishes a selective phase-regulation strategy to create customized nanostructures for diverse applications.