Synthesis and Isomorphous Substitutions in Lead Sodium Vanadate Apatite
Location
CSU Ballroom
Start Date
20-4-2015 10:00 AM
End Date
20-4-2015 11:30 AM
Student's Major
Chemistry and Geology
Student's College
Science, Engineering and Technology
Mentor's Name
Lyudmyla Stackpool
Mentor's Email Address
lyudmyla.stackpool@mnsu.edu
Mentor's Department
Chemistry and Geology
Mentor's College
Science, Engineering and Technology
Description
The world is experiencing a drastic fall in fuel resources and nature is greatly affected by the greenhouse gases. Therefore, it is paramount to do research on environmentally friendly and highly efficient sources of electric energy (fuel cells). This explains the recent rise in interest for solid state electrolytes. Vanadates with apatite structure (general formula M10 (XO4)6Y2, where M= Ca, Sr, Ba, Pb; X=P, V, As, Si; Y=OH, F, O, etc.) can be used as potential solid oxide electrolytes. Pbcontaining apatites play an essential role since only Pb-containing compounds retain the apatite structure in which the Y ions are absent; the structural channels are free which favor oxygen conductivity. The goal of our study was to establish synthetic conditions, chemical composition, and crystal structure of Pb-containing vanadates modified by rare-earth elements (REE). The substitution of Pr3+, Eu3+ for Pb2+ in systems Pb(8-x)REExNa2(VO4)6Ox/2 under the scheme: 2 Pb2++ (yields) 2REE3+ + O2- was examined. The solid solutions were synthesized by the solid-phase method at temperature of 600°C upon annealing for 32 hours and studied by XRD and SEM methods. According to the XRD, the substitution limits in systems Pb(8-x)REExNa2(VO4)6Ox/2 were found within the ranges 0 ≤ x ≤ 0.15 for Eu, 0 ≤ x ≤ 0.25 for Pr. It was found that the unit cell parameters a, c, and volume, v decrease monotonically with increasing x. Oxygen ions content in the structural channels increases with increasing x which leads to a gradual increase in conductivity.
Synthesis and Isomorphous Substitutions in Lead Sodium Vanadate Apatite
CSU Ballroom
The world is experiencing a drastic fall in fuel resources and nature is greatly affected by the greenhouse gases. Therefore, it is paramount to do research on environmentally friendly and highly efficient sources of electric energy (fuel cells). This explains the recent rise in interest for solid state electrolytes. Vanadates with apatite structure (general formula M10 (XO4)6Y2, where M= Ca, Sr, Ba, Pb; X=P, V, As, Si; Y=OH, F, O, etc.) can be used as potential solid oxide electrolytes. Pbcontaining apatites play an essential role since only Pb-containing compounds retain the apatite structure in which the Y ions are absent; the structural channels are free which favor oxygen conductivity. The goal of our study was to establish synthetic conditions, chemical composition, and crystal structure of Pb-containing vanadates modified by rare-earth elements (REE). The substitution of Pr3+, Eu3+ for Pb2+ in systems Pb(8-x)REExNa2(VO4)6Ox/2 under the scheme: 2 Pb2++ (yields) 2REE3+ + O2- was examined. The solid solutions were synthesized by the solid-phase method at temperature of 600°C upon annealing for 32 hours and studied by XRD and SEM methods. According to the XRD, the substitution limits in systems Pb(8-x)REExNa2(VO4)6Ox/2 were found within the ranges 0 ≤ x ≤ 0.15 for Eu, 0 ≤ x ≤ 0.25 for Pr. It was found that the unit cell parameters a, c, and volume, v decrease monotonically with increasing x. Oxygen ions content in the structural channels increases with increasing x which leads to a gradual increase in conductivity.
Recommended Citation
Tachago Kamdom, Estelle Sonya and Brontae Berkhoel. "Synthesis and Isomorphous Substitutions in Lead Sodium Vanadate Apatite." Undergraduate Research Symposium, Mankato, MN, April 20, 2015.
https://cornerstone.lib.mnsu.edu/urs/2015/poster_session_A/31
