Search NASA⌕ Search

DOE OSTI · 1663915

Materials Data on Hg3Pd8Se9 by Materials Project

Abstract

Pd8Hg3Se9 crystallizes in the orthorhombic Pmmn space group. The structure is three-dimensional. there are three inequivalent Pd sites. In the first Pd site, Pd is bonded to one Hg and five Se atoms to form distorted PdHgSe5 octahedra that share a cornercorner with one SeHgPd3 tetrahedra and edges with two equivalent PdHgSe5 octahedra. The Pd–Hg bond length is 2.89 Å. There are four shorter (2.55 Å) and one longer (2.65 Å) Pd–Se bond lengths. In the second Pd site, Pd is bonded in a 6-coordinate geometry to two Hg and four Se atoms. There are one shorter (2.85 Å) and one longer (2.98 Å) Pd–Hg bond lengths. There are a spread of Pd–Se bond distances ranging from 2.53–2.58 Å. In the third Pd site, Pd is bonded in a 6-coordinate geometry to one Hg and five Se atoms. The Pd–Hg bond length is 2.76 Å. There are a spread of Pd–Se bond distances ranging from 2.53–3.04 Å. There are two inequivalent Hg sites. In the first Hg site, Hg is bonded in a 5-coordinate geometry to four Pd and one Se atom. The Hg–Se bond length is 2.65 Å. In the second Hg site, Hg is bonded in a 4-coordinate geometry to four equivalent Pd atoms. There are four inequivalent Se sites. In the first Se site, Se is bonded in a 4-coordinate geometry to four Pd atoms. In the second Se site, Se is bonded in a 6-coordinate geometry to six Pd atoms. In the third Se site, Se is bonded to four Pd atoms to form distorted SePd4 trigonal pyramids that share corners with three equivalent SeHgPd3 tetrahedra, corners with three equivalent SePd4 trigonal pyramids, and edges with two equivalent SePd4 trigonal pyramids. In the fourth Se site, Se is bonded to three Pd and one Hg atom to form SeHgPd3 tetrahedra that share a cornercorner with one PdHgSe5 octahedra and corners with six equivalent SePd4 trigonal pyramids. The corner-sharing octahedral tilt angles are 76°.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

2020-05-02. Materials Data on Hg3Pd8Se9 by Materials Project. https://doi.org/10.17188/1663915

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related reports

Cyclic moisture reactivation of calcium sorbents for long duration thermochemical energy storage

The transition to a flexible and reliable energy infrastructure, using electro-thermal energy generation technologies such as geothermal, concentrated solar power, and nuclear, usually demands simultaneous advancement of thermal energy storage (TES) to support on-demand electricity generation and industrial applications while mitigating the inherent intermittency of renewable energy sources and power outages from direct energy generation. Among TES technologies, thermochemical energy storage (TCES) based on calcium looping emerges as a compelling high-power energy storage candidate due to its high reaction enthalpy, compatibility with elevated operating temperatures, and abundance of low-cost materials. However, the long-term durability of calcium-based sorbents for TCES is hindered by surface sintering and particle aggregation, leading to performance degradation over repeated thermal cycles. This study explores a moisture hydration-based strategy to regenerate a degraded calcium sorbent and mitigate performance degradation for long duration TCES. The addition of moisture transforms calcium oxide into calcium hydroxide and produces intercalation water layers, associated with a regenerated surface area and reduced calcium oxide crystallite size. Both these effects are beneficial in restoring the sorbents' reactivity for carbonization. Additionally, an optimized hydration-assisted reactivation protocol balances the recovered energy storage capacity with heating penalty required for moisture removal from hydrated samples, resulting in an enhanced energy storage capacity up to 176% compared to benchmark sorbents that undergo cycling without reactivation after 60 cycles. In conclusion, these results highlight the potential of hydration-assisted reactivation to enhance the long-term performance of TCES, providing an effective pathway to advancing electro-thermal storage technologies.

36 MATERIALS SCIENCE↗