(湘潭大學(xué) 化工學(xué)院，湘潭 411105)
摘 要: 利用X射線衍射(XRD)、傅里葉變換紅外光譜(FT-IR)、零電荷點(diǎn)pHPZC、循環(huán)伏安(CV)和電化學(xué)阻抗(EIS)等手段，研究鎂鐵水滑石(MgFe-LDHs)的表面化學(xué)性質(zhì)，揭示其表面酸堿性與電化學(xué)性能的關(guān)系。結(jié)果表明：當(dāng)Mg與Fe的摩爾比(n(Mg)/n(Fe))為3時(shí)MgFe-LDH (LDH-3)的結(jié)晶度最高，堿性最強(qiáng)，且遠(yuǎn)強(qiáng)于n(Mg)/n(Fe)為2的MgFe-LDH (LDH-2)和n(Mg)/n(Fe)為4的(LDH-4)的堿性。LDH-2的堿性略強(qiáng)于LDH-4的，但差異微小。層間CO32–與LDH層板金屬離子主要形成單齒和雙齒配位，其中，單齒配位體與強(qiáng)堿位點(diǎn)配位，形成Lewis堿位。表面堿性取決于Lewis強(qiáng)堿性位(CO32–單齒配位)的含量。用鎂鐵水滑石煅燒產(chǎn)物 (MgFe-LDOs) 修飾玻碳電極來研究其電化學(xué)性能。堿性越強(qiáng)(如LDO-3)，其氧化還原可逆性及導(dǎo)電性能越好。
關(guān)鍵字: 鎂鐵水滑石；表面酸堿性；配位；電化學(xué)性能；結(jié)晶度
（School of Chemical Engineering, Xiangtan University, Xiangtan 411105, China）
Abstract:The surface chemical characteristics of the Mg-Fe hydrotalcites (MgFe-LDHs) were determined using X-ray diffractometry (XRD), Fourier transform-infrared spectrometer (FT-IR), point of zero charge (pHPZC), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The relationship between the surfaceacid-base and electrochemical properties of the MgFe-LDHs was clarified. The results show that the MgFe-LDH with molar ratio of Mg to Fe (n(Mg)/n(Fe)) being 3 (LDH-3) has the highest crystallity structure with symmetrical crystals, indicating that the surface basicity of the LDH-3 is the strongest. And its basicity is much higher than those of ones with n(Mg)/n(Fe) of 2 (LDH-2) and 4 (LDH-4). The basicity of LDH-2 is slightly stronger than that of LDH-4. The monodentate and bidentate coordinations are formed by the interlayer CO32– anions coordinating with the metal ions in the brucite-like layers. The monodentate ligand coordinates with the strong basic sites, then Lewis basic sites form. The basicity depends on the content of Lewis basic sites. Mg-Fe hydrotalcite calcined samples (MgFe-LDOs) were used to modify glassy carbon electrode to study its electrochemical properties. The stronger the basicity (such as those of the LDO-3) is, the better the oxidation-reduction reversibility and conductivity are.
Key words: Mg-Fe hydrotalcite; urfaceacid-base property; coordination; electrochemical property; crystallinity
