现场表面拉曼光谱研究Fe-Mo合金诱导共沉积

现场表面拉曼光谱结果显示，在0．2mol·L-1Na2MoO4,pH＝4．0的溶液中，电位正于0．5V（vsSCE）时只观察到多钼酸盐的拉曼峰（940、880和450cm-1）．负于-0．5V时，出现中心位于730cm-1的宽峰．同时电极表面有蓝色膜生成．表明混合氧化态（MO（Ⅳ），MO（Ⅴ））氧化膜的形成．730cm-1的峰在-1．9V时仍然存在，说明氧化膜没有被进一步还原．在钼酸钠溶液中同时含有0．1mol·L-1FeSO4和0．2mol·L-1柠檬酸时，中间态氧化膜的拉曼峰的中心移到740cm-1．且峰强度随着电位从-1．3V负移到-1．9V而逐渐减弱并最终消失．电极表面沉积层呈银白色，说明由于Fe2 的存在，钼的中间态氧化膜的结构发生了变化，能够被进一步还原形成Fe－Mo合金，表现出诱导共沉积的特征．

In Situ Surface Raman Spectroscopy Study on Fe-Mo Alloy Induced-codeposition

The Fe-Mo alloy induced-codeposition has been studied by in situ surface Raman spectroscopy. In the solution containing 0.2mol•L-1 Na2MoO4．pH＝4．0．the Raman spectra showed three peaks at 940,880 and 450cm-1 corresponding to polymolybdated species on the surface at open circuit potential and -0.3V(vs SCE) at the potential-0.5V, new peaks at about 730, 560, 510, 470 cm-1 appeared in the spectra while a blue film was observed on the surface which can be attributed to mixed-oxidation molybdenum oxides formation. The peak at 730cm-1did not disappear even the potential moved to -1.9V, indication the film annot be further reduced. But in the solution of Na2MoO4 containing 0.1 mol•L-1 FeSO4 and 0.2mol•L-1 citric acid, the peak of mixed-oxidation oxides shifted to 740cm-1 and this peak could fade away gradually in potential region from -1.3 to -1.9V while a silver-white deposit emerged on the surface The results showed that the structure of mixed-oxidation Mo oxides film codeposited with Fe2+ was different from that of the film deposited without Fe2+. The former can be further reduced to form Fe-Mo alloy．