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Polyethylene glycol assisted one-pot hydrothermal synthesis of NiWO4/WO3 heterojunction for direct Methanol fuel cells
Electrochimica Acta ( IF 5.5 ) Pub Date : 2018-01-12 , DOI: 10.1016/j.electacta.2018.01.063
Mohamed Mokhtar Mohamed , M. Khairy , Salah Eid

A novel hetero-junction anode composed of NiWO4/WO3, formed at various metal molar ratios (Ni/W) and fabricated hydrothermally via simple salt solution addition method using polyethylene glycol, was characterized using XRD, TEM-SAED, N2 sorptiometry, UV–Vis diffuse reflectance and FTIR spectrometry. Increasing NiO especially at the Ni/W ratio of 4 stimulates the develop of a tailored morphology (nanoplates/nanowires with crystallites size of 11 nm) with entailed mesoporous surface texturing values (SBET = 100.7 m2/g and Vp = .186 cm3/g) exceeding those exhibited at Ni/W ratio of 1 and 2 and rather shows a monomodal type of pores at 3.5 nm. The electrocatalytic performances of all nanocomposites toward methanol oxidation (0.6 M) were examined in comparison with pristine NiO and WO3 samples by cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS) measurements. Strikingly, the NiWO4/WO3 electrode; synthesized at Ni/W ratio of 4, shows higher current density exceeding those of NiW(1:1) and NiW(2:1) by 3.4 and 2.6 fold, respectively. This pronounced electrocatalytic activity is mostly attributed to increasing the electrochemically active surface area of the former (16.9 cm2) and superior mesoporous nanostructures, which facilitate not only the diffusional electrochemical kinetics but also the long term cycle durability towards the CO poisoning species. This encountered stability was also due to the strong interaction between Ni and W to form small NiWO4 crystals of higher carrier density; as evaluated from the resistivity measurement, and to the hybridization with WO3 moieties of high electron transport properties, as confirmed by the EIS results.



中文翻译:

聚乙二醇辅助一锅法水热合成直接甲醇燃料电池的NiWO 4 / WO 3异质结

利用X射线衍射,TEM-SAED,N 2吸光法表征了一种新型的由NiWO 4 / WO 3组成的异质结阳极,该异质结阳极以各种金属摩尔比(Ni / W)形成,并通过简单的盐溶液添加法使用聚乙二醇水热法制备。 ,UV-Vis漫反射率和FTIR光谱法。NiO的增加,特别是在Ni / W比为4的情况下,会刺激定制形貌的发展(微晶尺寸为11 nm的纳米板/纳米线),并伴随有介孔表面纹理化值(S BET  = 100.7 m 2 / g和V p  = .186)厘米3/ g)超过在Ni / W比为1和2时表现出的那些,而是在3.5nm处显示出单峰类型的孔。通过循环伏安法(CV),计时电流法(CA)和电化学阻抗谱(EIS)测量,与原始NiO和WO 3样品相比,检查了所有纳米复合材料对甲醇氧化(0.6 M)的电催化性能。令人惊讶的是,NiWO 4 / WO 3电极;以4的Ni / W比合成的电流密度分别比NiW(1:1)和NiW(2:1)高3.4倍和2.6倍。这种明显的电催化活性主要归因于前者的电化学活性表面积增加(16.9 cm 2)和优异的中孔纳米结构,不仅有利于扩散电化学动力学,而且还具有针对CO中毒物质的长期循环耐久性。所遇到的稳定性还归因于Ni和W之间的强相互作用,从而形成了具有更高载流子密度的小的NiWO 4晶体。如通过电阻率测量所评估的,以及与具有高电子传输特性的WO 3部分的杂交,如通过EIS结果所证实的。

更新日期:2018-01-12
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