分类： 物理学 >> 交叉学科物理及相关领域的科学与技术 提交时间： 2018-03-30
摘要： Synthesis of low-cost, highly-active and durable non-platinum metal catalysts for methanol oxidation reaction (MOR) is always full of challenge. Here, Ni nanoparticles modified reduced graphene oxide (Ni/rGO) as an efficient non-platinum catalyst were synthesized by laser ablation of Ni target in graphene oxide (GO) solution and the following in situ reduction process. It found that GO played an important role to restrict the growth and aggregation of ultrafine nickel colloids (< 5 nm) in the process of laser ablation. The resulting Ni/rGO catalyst showed advantageous in active sites and charge transport resulting from the small particle size, uniform dispersion and electronic effect arising from the electron interactions between reduced graphene oxide (rGO) and Ni. The obtained Ni/rGO exhibited the ultrahigh catalytic mass activity of 1600 mA/mg, methanol saturation concentration (4 M), which was superior to that of the reported Ni-based catalysts. Remarkably the mass activities of Ni/rGO before and after 1000 cycles exceed that of the commercial Pt/C catalyst, indicating excellent catalytic activity and stability.
分类： 物理学 >> 交叉学科物理及相关领域的科学与技术 提交时间： 2018-03-30
摘要： Co-Ni layered double hydroxides (LDHs), as promising supercapacitor electrode materials with high specific capacity, have suffered poor rate property and cycle stability. By doping and topochemical oxidation of Ni ions is considered as efficivent rout to overcome these drawbacks. In this work, Ni3+ doped cobalt-nickel layered double hydroxides (Co-Ni-LDHs) were synthesized by pluse laser ablation of Ni taget in CoCl2 aqeous solution. The existence of Ni3+ ions doped in Co-Ni-LDHs decline the conductive resistance, and increase the mobility of surface charge and transfer rate of electrolyte. As a results, the Ni3+ doped Co-Ni-LDHs display a maximum specific capacitance of 2275 F/g and 1450 F/g at the current density of 1 A/g and 20 A/g, respectivly, indicating a high rate specific capacitance. Moreover, the capacitance retention is to be 80% after 1800 cycles at the current density of 6 A/g, manifesting good cycling stability of Ni3+ doped Co-Ni-LDHs.
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