Formation of the cerium orthovanadate $Ce V O_{4}$ : $DFT + U$ study

We report density functional theory calculations of the structural, electronic, and thermodynamic properties of cerium orthovanadate (

Ce V O_{4}

) employing the local density approximation (LDA), generalized gradient approximation (GGA-PBE),

LDA + U

, and

GGA − PBE + U

functionals. The

LDA + U

GGA − PBE + U

, LDA, and GGA-PBE equilibrium volumes deviate by

- 2.4 %

+ 3.6 %

- 7.4 %

, and

- 0.8 %

, respectively, from experimental results.

DFT + U

(DFT) predicts an antiferromagnetic (ferromagnetic) insulating (metallic) ground state, which is in agreement with experimental observations.

DFT + U

yields Ce and V ions in the

III +

and

V +

oxidation state, respectively.

Ce V O_{4}

can be obtained by the reaction between

{Ce}_{2} O_{3}

and

V_{2} O_{5}

[

\frac{1}{2} {Ce}_{2} O_{3} (s) + \frac{1}{2} V_{2} O_{5} (s) \to Ce V O_{4} (s)

] under an inert atmosphere, which is described as exoenergetic

(∣ Δ H_{0} ∣ = 1.6 - 1.8 eV)

by all functionals. The reaction

\frac{1}{2} {Ce}_{2} O_{3} (s) + \frac{1}{2} V_{2} O_{5} (s) \to Ce O_{2} (s) + V O_{2} (s)

is exoenergetic with

∣ Δ H_{0} ∣ = 0.75

, 0.25, 1.70, and

1.24 eV

for

LDA + U

GGA − PBE + U

, LDA, and GGA-PBE, respectively. Hence,

V^{V +}

is more easily reduced to

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Formation of the cerium orthovanadateCeVO4:DFT+Ustudy