Strong Negative Thermal Expansion in a Low-Cost and Facile Oxide of Cu₂P₂O₇

Abstract

Negative thermal expansion (NTE) behaviors have been observed in various types of compounds. The achievement in the merits of promising low-cost and facile NTE oxides remains challenging. In the present work, a simple and low-cost Cu 2 P 2 O 7 has been found to exhibit the strongest NTE among the oxides (α V ∼ −27.69 × 10 −6 K −1 , 5−375 K). The complex NTE mechanism has been investigated by the combined methods of high-resolution synchrotron X-ray diffraction, neutron powder diffraction, X-ray pair distribution function, extended X-ray absorption fine structure spectroscopy, and density functional theory calculations. Interesting, the direct experimental evidence reveals that the coupling twist and rotation of PO 4 and CuO 5 polyhedra are the inherent factors for the NTE nature of Cu 2 P 2 O 7 , which is triggered by the transverse vibrations of oxygen atoms. The present new NTE material of Cu 2 P 2 O 7 also has been verified for the practical application.

The role of average atomic volume in predicting negative thermal expansion: The case of REFe(CN)6

“…2c). Such opposite thermal expansion behavior through similar experimental measurements is also observed in other NTE materials such as ZrW 2 O 8 [35], TiCo(CN) 6 [36] and Cu 2 P 2 O 7 [37]. In order to further study the thermal vibrations, we also extracted the atomic mean square relative displacements (MSRDs) [38] of Lu-N and Fe-C atomic pairs.…”

A Reconstructed Cu2P2O7 Catalyst for Selective CO2 Electroreduction to Multicarbon Products

“…Copper pyrophosphate (Cu 2 P 2 O 7 ) is a structurally well‐defined A 2 M 2 O 7 ‐type compound, with CuO 5 layer and PO 4 polyhedra layer stacking, [9] but its application in electrocatalysis especially the CO 2 RR has been rarely reported. In this work, we synthesized a Cu 2 P 2 O 7 catalyst by introducing phosphorus into the lattice of cupric oxide (CuO) as a starting material for electrochemical in situ reconstruction.…”

Anomalous Thermal Expansion in Ta2WO8 Oxide Semiconductor over a Wide Temperature Range

“…The PTE materials can meet the needs of most daily applications. However, low/zero thermal expansion is very rare but necessary in some fields that are sensitive to dimensional changes of materials, such as electronic devices, thermoelectric devices, automatic control, and aerial cameras. , Since the negative thermal expansion (NTE) mechanism of ZrW 2 O 8 has been studied, rapid progress has been made in NTE materials, covering oxides, − alloys, − nitrides, − cyanides, − and fluorides, , which opens up a way for achieving low/zero thermal expansion materials or composite materials.…”