LaNiO_3/Pd复合薄膜电极材料在碱性溶液中的电化学行为研究

Electrochemical Properties of Pd/LaNiO_3 Film Electrodes in Alkaline Electrolyte Solution

用射频磁控溅射法在Si(111)衬底上沉积制备金属Pd膜、LaNiO3单层膜和Pd/LaNiO3复合薄膜,利用XRD,SEM,EDS能谱、四元探针和电化学方法系统研究了退火处理和表面覆Pd对Pd/LaNiO3复合薄膜电极的相组织结构、表面形貌、电学以及电化学储氢行为的影响。结果表明,700℃退火1 h后,LaNiO3薄膜具有结晶度较佳的钙钛矿型菱方结构组织和最小的电阻率(0.79 mΩ·cm),退火温度高于800℃后,LaNiO3菱方型结构组织开始分解,电阻率增加。LaNiO3薄膜在空气中退火后其表面化学吸附氧转变为晶格氧,导致LaNiO3薄膜氧元素含量明显增加。电化学测试结果表明,在碱液中金属Pd膜具有良好的析氢电催化活性和较好的电化学储氢性能,其最大放电容量为130 mAh·g-1。退火态LaNiO3单膜电极放电容量很小(27 mAh·g-1),当表面覆Pd后退火态LaNiO3/Pd复合薄膜电极放电容量增加至181 mAh·g-1,扣除其表面Pd膜吸氢容量后LaNiO3薄膜电极的实际放电容量最高达到400 mAh·g-1。LaNiO3表面镀Pd后能极大改善和提高LaNiO3薄膜电极的电催化活性和电化学储氢容量。

Pd, LaNiO3 influences of annealing and LaNiO3/Pd films were prepared by RF magnetron sputtering on Si（ 111 ） substrate. The and surface coating Pd on the phase structure, morphology, combining states of oxygen in the lattice, resistivity and electrochemical properties were investigated by XRD, XPS, SEM, EDS, four probe and electrochemical method. The results showed that after annealed at 700 ℃for 1 h, LaNiO3 films had better crystal- linity with rhombohedral perovskite structure and the minimum resistivity 0.79 mΩ·cm. LaNiO3 perovskite structure was changed and the resistivity increased when the annealing temperature was higher than 800 ℃. The results of electrochemical measurement found that metal Pd film had good electro-catalytic activity for hydrogen evolution and good electrochemical hydrogen storage properties in alkaline, and the maximum discharge capacity was 130 mAh.g The discharge capacity of LaNiO3 film was low, and the discharge capacity of LaNiO3/Pd composite film was 181 mAh·g^-1 after after removing annealing. But by calculating the discharge capacity of LaNiO3/Pd film electrode was 400 mAh·g^-1 the capacity contribution of Pd. The electrocatalytic activity and electrochemical maximum capacity of Pd-capped LaNiO3 composite film electrode were significantly improved.