Influence of A/B stoichiometry ratio on exsolution behavior of pulsed electric current promoted perovskite
The perovskite oxide was successfully produced by applying PEC(pulsed electric current)treatment technique with(La0.7 Sr0.3)xTi0.93Co0.07O3 perovskite oxides as the substrate active material within 90 s under the pulsed parameter of 600 V-3 Hz.The ratio of A-site to B-site in ABO3(perovskite)under normal stoichiometry is nA/nB=1.Combined with two different stoichiometric ratio cases of A-site deficiency(x=0.8,x=0.9,nA/nB＜1)and A-site overdetermination(x=1.2,nA/nB＞1).XRD(X-ray diffractometer)was used to analyze the new Co singlet diffraction peaks in the A-site-deficient perovskite after pulse current treatment at x=0.8 and x=0.9.SEM(scanning electron microscope)and TEM(Transmission electron microscopy)observe that there are obvious Co nanoparticles dissolved on the surface in the A-site-deficient perovskite after pulse electric current treatment with a very homogeneous distribution.The electrochemical tests show that the oxidation peaks in the pulsed A-site-deficient perovskites at x=0.9 are very high,the area is the largest and the CV(cyclic voltamnetry)curve is closer to the rectangle,which has better reversibility and good charge transfer ability.The comprehensive analysis finds that,when the A-site is absent,the pulsed-current-treated chalcocite oxides are helpful to form the oxygen vacancies,which is more conducive to triggering the exsolution of chalcocite B-site Co reduction into metal nanoparticles exsolution,improving the electronic conductivity and catalytic activity.
pulsed electric currentperovskitenanoparticleexsolution
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