Abstract
Crystal chemical design principles were applied to synthesise novel U4+ dominant and titanium excess betafite phases Ca1.15(5)U0.56(4)Zr0.17(2)Ti2.19(2)O7 and Ca1.10(4)U0.68(4)Zr0.15(3)Ti2.12(2)O7, in high yield (85–95 wt%), and ceramic density reaching 99% of theoretical. Substitution of Ti on the A-site of the pyrochlore structure, in excess of full B-site occupancy, enabled the radius ratio (rA/rB = 1.69) to be tuned into the pyrochlore stability field, approximately 1.48 ≲ rA/rB ≲ 1.78, in contrast to the archetype composition CaUTi2O7 (rA/rB = 1.75). U L3-edge XANES and U 4f7/2 and U 4f5/2 XPS data evidenced U4+ as the dominant speciation, consistent with the determined chemical compositions. The new betafite phases, and further analysis reported herein, point to a wider family of actinide betafite pyrochlores that could be stabilised by application of the underlying crystal chemical principle applied here.
| Original language | English |
|---|---|
| Article number | 10328 |
| Journal | Scientific Reports |
| Volume | 13 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - 26 Jun 2023 |
Bibliographical note
Funding Information:NCH, SKS, CLC and LMM are grateful for financial support from the Nuclear Decommissioning Authority and EPSRC under grant numbers EP/M026566/1, EP/S01019X/1, EP/N017870/1, EP/R511754/1 and EP/N017374/1. SKS acknowledge the fund from NSFC (52172064). LMM acknowledge the studentships from EPSRC (EP/R513313/1 and EP/N509735/1). This research utilised the MIDAS/HADES facility at The University of Sheffield established with financial support from EPSRC and BEIS, under grant EP/T011424/1. We acknowledge Diamond Light Source for allocation of beam-time at Beamline B18 (Proposal SP17782 and SP24074-1). XPS measurement was performed in European Commission, Joint Research Centre (JRC), Institute for Transuranium Elements (ITU).
Funding Information:
NCH, SKS, CLC and LMM are grateful for financial support from the Nuclear Decommissioning Authority and EPSRC under grant numbers EP/M026566/1, EP/S01019X/1, EP/N017870/1, EP/R511754/1 and EP/N017374/1. SKS acknowledge the fund from NSFC (52172064). LMM acknowledge the studentships from EPSRC (EP/R513313/1 and EP/N509735/1). This research utilised the MIDAS/HADES facility at The University of Sheffield established with financial support from EPSRC and BEIS, under grant EP/T011424/1. We acknowledge Diamond Light Source for allocation of beam-time at Beamline B18 (Proposal SP17782 and SP24074-1). XPS measurement was performed in European Commission, Joint Research Centre (JRC), Institute for Transuranium Elements (ITU).
Publisher Copyright:
© 2023, The Author(s).