La_1-xSr_xMnO₃电催化剂的制备及析氧性能研究

Preparation and Oxygen Evolution Performance of La_1-xSr_xMnO₃ Electrocatalyst

本文采用溶胶凝胶法成功制备了不同Sr掺杂的La1−xSrxMnO3 (LSMO, x = 0, 0.15, 0.33, 0.55)钙钛矿型电催化剂,分析了LSMO钙钛矿的晶体结构和微观形貌,利用XPS技术表征了LSMO样品的Mn离子价态和含氧类型,使用电化学工作站进行了循环伏安法、线性扫描伏安法和交流阻抗法等测试,研究了LSMO电催化剂的析氧反应(OER, oxygen evolution reaction)性能。结果表明:随着Sr掺杂量的增加,样品的XRD衍射峰峰强逐渐变弱,平均晶粒尺寸逐渐下降,吸附氧和Mn4+的含量逐渐增加;且当x = 0.55时,LSMO具有最优的OER性能:在1.7 V vs RHE的电位下具有1.04 mA·cm−2的电流密度,244 mV·dec−1的Tafel斜率和0.92 mF·cm−2的双电层电容。本研究为钙钛矿锰氧化物电催化剂的应用奠定了一定的理论和研究基础。

In this paper, different Sr doped La1−xSrxMnO3 (LSMO, x =0, 0.15, 0.33, 0.55) perovskite type electrocatalysts have been successfully prepared by Sol-Gel method. The crystal structure and microstructure of LSMO perovskite have been analyzed. And the Mn ion valence and oxygen type of LSMO samples have been characterized by XPS technology. Cyclic voltammetry, linear sweep voltammetry and AC impedance spectroscopy have been used to study the performance of LSMO electrocatalyst for oxygen evolution reaction (OER). The results show that with the increase of Sr doping amount, the XRD diffraction peak intensity of the sample gradually weakens, the average grain size gradually decreases, and the content of adsorbed oxygen and Mn4+ gradually increases;And at x = 0.55, LSMO has optimal OER performance: a current density of 1.04 mA·cm−2 at a potential of 1.7 V vs RHE, a Tafel slope of 244 mV·dec−1, a Cdl of 0.92 mF·cm−2. This study lays a theoretical and research foundation for the application of perovskite manganese oxide electrocatalysts.