Neiva Eduardo G C, Souza Victor H R, Huang Kai, Pénicaud Alain, Zarbin Aldo J G
Departamento de Química, Universidade Federal do Paraná (UFPR), CP 19081, CEP 81531-990, Curitiba, PR, Brazil.
CNRS, Centre de Recherche Paul Pascal (CRPP), UPR 8641, F-33600 Pessac, France; Univ. Bordeaux, CRPP, UPR 8641, F-33600 Pessac, France.
J Colloid Interface Sci. 2015 Sep 1;453:28-35. doi: 10.1016/j.jcis.2015.04.036. Epub 2015 Apr 30.
Nanocomposites between nickel nanoparticles and graphene were obtained starting from nickel cations and graphenide solutions (negatively charged graphene layers) as both reducing agent to nickel cations and graphene source. Different nanomaterials were obtained in two different solvents, N-methyl-2-pyrrolidone (NMP) and tetrahydrofuran (THF), with different nickel/graphene ratios. The nanomaterials were characterized by UV-Vis spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDS), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). All the samples consist of large graphene layers highly decorated with crystalline nickel nanoparticles, of size ranging from 2 to 10 nm. Thin films of the samples were deposited on indium-tin oxide (ITO) substrates and electrochemically characterized in alkaline medium, leading to Ni(OH)2/NiOOH redox pair, where the increase of the nickel proportion in the nanocomposites resulted in higher peak currents. The samples obtained in NMP showed the best performance with a fivefold increase of the peak currents, consistent with the lower charge transfer resistance as seen by electrochemical impedance spectroscopy (EIS).
从镍阳离子和石墨烯溶液（带负电荷的石墨烯层）出发，制备了镍纳米颗粒与石墨烯的纳米复合材料，其中石墨烯层既是镍阳离子的还原剂，又是石墨烯源。在两种不同的溶剂N-甲基-2-吡咯烷酮（NMP）和四氢呋喃（THF）中，以不同的镍/石墨烯比例获得了不同的纳米材料。通过紫外-可见光谱、透射电子显微镜（TEM）、扫描电子显微镜（SEM）、热重分析（TGA）、原子力显微镜（AFM）、X射线光电子能谱（XPS）、能量色散X射线能谱（EDS）、循环伏安法（CV）和电化学阻抗谱（EIS）对纳米材料进行了表征。所有样品均由高度装饰有结晶镍纳米颗粒的大石墨烯层组成，镍纳米颗粒尺寸在2至10nm之间。将样品薄膜沉积在氧化铟锡（ITO）衬底上，并在碱性介质中进行电化学表征，得到Ni(OH)2/NiOOH氧化还原对，其中纳米复合材料中镍比例的增加导致峰值电流更高。在NMP中获得的样品表现出最佳性能，峰值电流增加了五倍，这与电化学阻抗谱（EIS）显示的较低电荷转移电阻一致。
