Search NASA⌕ Search

DOE OSTI · 1187618

Materials Data on Nd3Sb4Pt7 by Materials Project

Abstract

Nd3Pt7Sb4 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are two inequivalent Nd3+ sites. In the first Nd3+ site, Nd3+ is bonded to six Pt+1.43- atoms to form NdPt6 octahedra that share corners with two equivalent PtNd4Sb2Pt6 cuboctahedra and edges with two equivalent NdPt6 octahedra. There are four shorter (3.29 Å) and two longer (3.33 Å) Nd–Pt bond lengths. In the second Nd3+ site, Nd3+ is bonded in a 8-coordinate geometry to eight Pt+1.43- atoms. There are a spread of Nd–Pt bond distances ranging from 2.98–3.22 Å. There are four inequivalent Pt+1.43- sites. In the first Pt+1.43- site, Pt+1.43- is bonded in a 9-coordinate geometry to four Nd3+, one Pt+1.43-, and four Sb+0.25+ atoms. The Pt–Pt bond length is 2.95 Å. There are a spread of Pt–Sb bond distances ranging from 2.61–2.84 Å. In the second Pt+1.43- site, Pt+1.43- is bonded in a 9-coordinate geometry to three Nd3+, three Pt+1.43-, and three equivalent Sb+0.25+ atoms. There are two shorter (2.84 Å) and one longer (2.85 Å) Pt–Pt bond lengths. There are two shorter (2.65 Å) and one longer (2.79 Å) Pt–Sb bond lengths. In the third Pt+1.43- site, Pt+1.43- is bonded to four equivalent Nd3+, six Pt+1.43-, and two equivalent Sb+0.25+ atoms to form distorted PtNd4Sb2Pt6 cuboctahedra that share corners with two equivalent NdPt6 octahedra and faces with two equivalent PtNd4Sb2Pt6 cuboctahedra. The corner-sharing octahedral tilt angles are 63°. All Pt–Pt bond lengths are 2.98 Å. Both Pt–Sb bond lengths are 3.03 Å. In the fourth Pt+1.43- site, Pt+1.43- is bonded in a 12-coordinate geometry to two equivalent Nd3+, five Pt+1.43-, and three Sb+0.25+ atoms. There are two shorter (2.73 Å) and one longer (2.98 Å) Pt–Sb bond lengths. There are two inequivalent Sb+0.25+ sites. In the first Sb+0.25+ site, Sb+0.25+ is bonded in a 6-coordinate geometry to six Pt+1.43- atoms. In the second Sb+0.25+ site, Sb+0.25+ is bonded in a 5-coordinate geometry to five Pt+1.43- atoms.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

2020-07-15. Materials Data on Nd3Sb4Pt7 by Materials Project. https://doi.org/10.17188/1187618

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↗