Chalcogenide phase change materials based on germanium-antimony-tellurides (GST-PCMs) have shown outstanding properties in non-volatile memory (NVM) technologies due to their high write and read speeds, reversible phase transition, high degree of scalability, low power consumption, good data retention, and multi-level storage capability. However, GST-based PCMs have shown recent promise in other domains, such as in spatial light modulation, beam steering, and neuromorphic computing. This paper reviews the progress in GST-based PCMs and methods for improving the performance within the context of new applications that have come to light in recent years.

Designing and synthesizing a highly active single atom catalyst, especially monodispersed noble-metal atoms fixed in two-dimensional layered double hydroxide (LDH) nanostructures, is crucial in accelerating the slow oxygen evolution reaction (OER). Here, Ru single atoms (SAs) are stabilized on NiFe LDH (SARu/NiFe LDH) via an oxygen-coordinated bond after a facile solution reduction procedure. The OER activity evaluation at similar mass loading on glassy carbon reveals that SARu/NiFe LDH shows more activity than pure NiFe LDH in basic media, possessing 99.3% of Faradaic efficiency based on rotating ring-disk electrode measurement. This is mainly due to a strong synergy between Ru SAs and NiFe LDH support. Furthermore, these supported catalysts are developed to an integrative 3D electrode in situ of the nickel foam with a higher specific surface area, which needs only an ultralow overpotential of 196 mV at 10 mA cm–2. This is one of the most efficient electrode containing monoatomic components to date. Theoretical calculations suggests that active sites of Ru can facilitate the rearrangement of electrons and optimize the binding energy both SARu/NiFe LDH catalyst and intermediates during the OER, thereby improving the intrinsic OER activity. This study provides a general avenue to developing efficiently monoatomic and even multiatomic catalysts in the future.

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Improving the intrinsic catalytic activity of NiFe layered double hydroxide (LDH), which is a benchmark electrocatalyst for oxygen evolution reaction (OER), is a significant challenge. In the present study, we doped ruthenium ions into NiFe LDH (Ru-NiFe LDH) to accelerate the OER kinetics. Electrochemical measurements of NiFe LDH and Ru-NiFe LDH at similar mass loadings showed that Ru-NiFe LDH demonstrated a higher OER activity than that of NiFe LDH. Ru-NiFe LDH only requires an overpotential of 246 mV at 10 mA cm-2 in alkaline media. This is attributed to ruthenium doping primarily, which can promote the catalytic activity of Fe sites and boost the electronic interaction among the Ni, Fe, and Ru metals according to the theoretical calculations. Ru-NiFe LDH is stable during OER stability measurements, which was confirmed by structure and elemental analysis. These findings will provide a useful approach for promoting the intrinsic activity of multi-metallic (oxy) hydroxide electrocatalysts toward the OER.