中文摘要：

以Vulcan XC-72炭黑为载体,通过对炭载体石墨化处理和表面化学修饰,将其与化学沉淀法制备的纳米级LaMnO3颗粒共混,再经特定温度下煅烧,制备出改性炭黑-LaMnO3复合材料. X射线光电子能谱和热重分析表明,当煅烧温度在300℃时,炭载体与LaMnO3纳米颗粒之间形成了大量C-O-M （M = La, Mn）化学键.扫描电子显微镜和高分辨透射电子显微镜分析发现,纯相LaMnO3纳米颗粒主要呈现短棒、三支棒或竹节棒的形貌特征,炭载体则为具有完整石墨层的空心球结构, LaMnO3均匀分散在炭载体上.在25℃,1 mol/L NaOH溶液中的电化学测试结果表明,成分比（LaMnO3：C）为2：3的复合材料具有很高的氧还原电催化活性,氧还原反应电子数为3.81,中间产物H2O2产率为9.5%,其活性接近商业Pt/C催化剂（E-TEK）.高的氧还原电催化活性主要归因于LaMnO3纳米颗粒与炭载体之间形成了大量共价键.

英文摘要：

Covalent coupling between LaMnO3 nanoparticles and carbon black to produce a composite catalyst for oxygen reduction reaction （ORR） was achieved by physical mixing of modified carbon and perovskite-type LaMnO3 nanoparticles, followed by sintering at different temperatures. Perovskitetype LaMnO3 nanoparticles were first synthesized via chemical precipitation, and the carbon support （Vulcan XC-72） was modified using graphitization, followed by HNO3 and ammonia treatments. The morphology and electronic states of the carbon black-LaMnO3 hybrid catalyst were characterized by scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The loaded LaMnO3 particles featured rod-like, three bars-like, and bamboo rod-like structures and were homogeneously dispersed in the carbon matrix that featured a hollow spherical structure. At a sintering temperature of about 300 ℃, C-O-M （M = La, Mn） bonds formed at the interface between the carbon and LaMnO3 nanoparticles. Electrochemical measurements in 1 mol/L NaOH showed that the carbon-LaMnO3 hybrid prepared at a LaMnO3/GCB mass ratio of 2：3 displayed the highest electrocatalytic activity towards ORR among all the synthesized hybrid catalysts. The electrocatalytic activity was comparable with that obtained by commercial Pt/C catalyst （E-TEK）. The average electron transfer number of ORR was ~3.81, and the corresponding yield of the hydrogen peroxide intermediate was ~9.5%. The remarkably improved electrocatalytic activity towards ORR was likely because of the formation of covalent bonds （C-O-M） between the LaMnO3 nanoparticles and carbon that can effectively enhance the ORR kinetics. This information is important to understand the physical origin of the electrocatalytic activity of carbon-supported rare earth oxides as catalysts for ORR.