Kumar Pravin, Jena Paramananda, Patro P K, Lenka R K, Sinha A S K, Singh Prabhakar, Singh Rajendra Kumar
Department of Physics, Institute of Science , Banaras Hindu University , Varanasi 221005 , India.
School of Material Science of Engineering and Technology, Indian Institute of Technology , Banaras Hindu University , Varanasi 221005 , India.
ACS Appl Mater Interfaces. 2019 Jul 10;11(27):24659-24667. doi: 10.1021/acsami.9b03481. Epub 2019 Jun 27.
Lanthanum (La)-doped double perovskites SrCoMoO (SrLaCoMoO, 0.00 ≤ ≤ 0.03) were synthesized via the citrate-nitrate autocombustion route. The Reitveld refinement analysis of X-ray diffraction reveals the tetragonal symmetry as the main phase with space group 4/ and also confirms the presence of some peaks corresponding to extra phase SrMoO. The SEM micrograph images reflect that grains are in irregular shape and sizes for all samples. Average grain size gradually decreases with the increase of the SrMoO phase. The X-ray photoelectron spectroscopy (XPS) analysis confirms the presence of mixed valence states of Mo/Mo, Co/Co, and O-lattice/O-chemisorbed/O-physisorbed species. Coefficient of thermal expansion (CTE) analysis shows that the particular composition SrLaCoMoO has the lowest CTE value among the compositions studied. The electrical conductivity of SrCoMoO is enhanced effectively by doping La at Sr sites. The measured area-specific resistance (ASR) for the composition SrLaCoMoO (SLCM03) is found to be appreciably low, ∼0.053 Ohm cm at 800 °C. The obtained highest electrical conductivity with the lowest activation energy and low ASR value for the composition SrLaCoMoO encompasses it as a promising candidate for anode material in the intermediate-temperature solid oxide fuel cell (IT-SOFC) application.
通过柠檬酸盐 - 硝酸盐自燃烧法合成了镧（La）掺杂的双钙钛矿SrCoMoO（SrLaCoMoO，0.00 ≤ ≤ 0.03）。X射线衍射的Rietveld精修分析表明，四方对称是主要相，空间群为4/，同时也证实了存在一些对应于额外相SrMoO的峰。扫描电子显微镜（SEM）显微图像显示，所有样品的晶粒形状和尺寸均不规则。随着SrMoO相的增加，平均晶粒尺寸逐渐减小。X射线光电子能谱（XPS）分析证实了Mo/Mo、Co/Co以及O晶格/O化学吸附/O物理吸附物种的混合价态的存在。热膨胀系数（CTE）分析表明，在所研究的成分中，特定成分SrLaCoMoO的CTE值最低。通过在Sr位点掺杂La，有效地提高了SrCoMoO的电导率。发现成分SrLaCoMoO（SLCM03）在800°C时的测量面积比电阻（ASR）相当低，约为0.053欧姆·厘米。对于成分SrLaCoMoO所获得的最高电导率、最低活化能和低ASR值，使其成为中温固体氧化物燃料电池（IT - SOFC）应用中阳极材料的有前景的候选者。
