PDF(Pubmed)
Abstract：
Transition metal oxides are a great alternative to less expensive hydrogen evolution reaction (HER) catalysts. However, the lack of conductivity of these materials requires a conductor material to support them and improve the activity toward HER. On the other hand, carbon paste electrodes result in a versatile and cheap electrode with good activity and conductivity in electrocatalytic hydrogen production, especially when the carbonaceous material is agglomerated with ionic liquids. In the present work, an electrode composed of multi-walled carbon nanotubes (MWCNTs) and cobalt ferrite oxide (CoFe2O4) was prepared. These compounds were included on an electrode agglomerated with the ionic liquid N-octylpyridinium hexafluorophosphate (IL) to obtain the modified CoFe2O4/MWCNTs/IL nanocomposite electrode. To evaluate the behavior of each metal of the bimetallic oxide, this compound was compared to the behavior of MWCNTs/IL where a single monometallic iron or cobalt oxides were included (i.e., α-Fe2O3/MWCNTs/IL and Co3O4/MWCNTs/IL). The synthesis of the oxides has been characterized by X-ray diffraction (XRD), RAMAN spectroscopy, and field emission scanning electronic microscopy (FE-SEM), corroborating the nanometric character and the structure of the compounds. The CoFe2O4/MWCNTs/IL nanocomposite system presents excellent electrocatalytic activity toward HER with an onset potential of -270 mV vs. RHE, evidencing an increase in activity compared to monometallic oxides and exhibiting onset potentials of -530 mV and -540 mV for α-Fe2O3/MWCNTs/IL and Co3O4/MWCNTs/IL, respectively. Finally, the system studied presents excellent stability during the 5 h of electrolysis, producing 132 μmol cm-2 h-1 of hydrogen gas.
摘要：
过渡金属氧化物是较便宜的析氢反应(HER)催化剂的很好的替代品。然而,这些材料缺乏导电性需要导体材料来支撑它们并提高对HER的活性。另一方面,碳糊电极导致在电催化制氢中具有良好的活性和导电性的多功能和廉价的电极，特别是当含碳材料与离子液体团聚时。在目前的工作中,制备了由多壁碳纳米管（MWCNTs）和钴铁氧体氧化物（CoFe2O4）组成的电极。将这些化合物包含在与离子液体N-辛基吡啶鎓六氟磷酸盐（IL）团聚的电极上，以获得修饰的CoFe2O4/MWCNT/IL纳米复合电极。为了评估双金属氧化物的每种金属的行为，将该化合物与包含单一金属铁或钴氧化物的MWCNT/IL的行为进行比较（即，α-Fe2O3/MWCNTs/IL和Co3O4/MWCNTs/IL)。氧化物的合成已通过X射线衍射（XRD）进行了表征，拉曼光谱,场发射扫描电子显微镜（FE-SEM），证实了化合物的纳米特征和结构。CoFe2O4/MWCNTs/IL纳米复合体系对HER表现出优异的电催化活性，起始电位为-270mV与RHE,与单金属氧化物相比，活性增加，α-Fe2O3/MWCNTs/IL和Co3O4/MWCNTs/IL的起始电位为-530mV和-540mV，分别。最后,所研究的系统在电解5小时内表现出优异的稳定性，产生132μmolcm-2h-1的氢气。
