Mercury is a metal with special physical and chemical properties. High pressure can significantly alter its crystal structures and interatomic interactions. However, vibration-related experimental data of mercury under high pressure have been scarce for a long time, which limits the in-depth understanding of its high-pressure phase transition mechanisms. To fill this research gap, this study systematically investigate the structural transformations and evolution of vibrational mode of mercury under high pressure. This was achieved by integrating low-wavenumber high-pressure confocal Raman spectroscopy, in-situ diamond anvil cell (DAC) techniques, and first-principles calculations. The study successfully detected the vibrational signals of two solid phases of mercury under high pressure for the first time, revealed the characteristics of pressure-dependent vibrational frequencies, and further calculated the relevant thermodynamic parameters of the two phases. The experimental data is highly consistent with the reported structural phase transitions of mercury, filling the long-standing experimental gap in this field and providing key experimental support for an in-depth understanding of the phase transition behaviors and related mechanisms of mercury under high pressure.

Efficient industrial hydrogen production via water splitting hinges on the development of highly effective oxygen evolution catalysts and a clear understanding of their catalytic mechanisms. Among various strategies, exploiting the synergistic effects of transition metals has shown great promise, although the underlying mechanisms remain elusive. Here, we investigate bi-transition metal borides, Mo₂MB₂ (M = Co and Ni), as a model system to unravel these synergistic effects and the evolution of active species during the oxygen evolution reaction (OER). Using combined in-situ and ex-situ characterization techniques, we monitor the structural and valence changes of constituent elements in real time. We find that Mo and B undergo oxidation and dissolution at the anode, initiating distinct evolutionary pathways. In Mo₂CoB₂, rapid structural collapse leads to the formation of γ-CoOOH as the active species. In contrast, Mo₂NiB₂ exhibits a more gradual surface-driven transformation, producing γ-NiOOH and Ni–O–Mo species. Chronopotentiometry testing reveals continued Mo and B dissolution, culminating in the transition of γ-phases to amorphous states, followed by recrystallization into β-phases. This study provides critical insights into dissolution-induced structural evolution, active species dynamics, and the synergistic interactions between Mo/B and Co/Ni during OER catalysis.