Liu Fan, Wang Liming, Yang Weijun, Liu Enqing, Huang Can
College of Chemistry and Chemical Engineering, Hunan University Changsha 410082 China
RSC Adv. 2019 Mar 6;9(13):7440-7446. doi: 10.1039/c8ra10222h. eCollection 2019 Mar 1.
High purity birnessite was synthesized and exfoliated into a negatively charged monolayer structure. A positively charged 5, 10, 15, 20-tetrakis (4-aminophenyl) manganese porphyrin (MnTAPP) was synthesized. Driven by the electrostatic force and the coordination effect of the amino nitrogen on the manganese ion in birnessite, the single-layer birnessite was reassembled with MnTAPP, forming a new sandwich-type catalytic composite MnTAPP@bir. The structure and chemical properties of the composite were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA) and Brunauer-Emmett analysis (BET). Electrocatalytic studies showed that the MnTAPP@bir exhibited an overpotential for water oxidation of 450 mV (at 10 mA cm) and a Tafel slope of 121.5 mV dec compared to birnessite with 700 mV (at 10 mA cm) and 230 mV dec. Impedance spectroscopy results suggested that the charge transfer resistivity of MnTAPP@bir was significantly lower than that of birnessite, suggesting that MnTAPP in the interlayer increased the conductivity of birnessite. Through a chronoamperometry test, the new material also showed excellent stability within 4000 s.
合成了高纯度水钠锰矿，并将其剥离成带负电荷的单层结构。合成了带正电荷的5,10,15,20-四（4-氨基苯基）锰卟啉（MnTAPP）。在静电作用以及水钠锰矿中氨基氮对锰离子的配位作用驱动下，单层水钠锰矿与MnTAPP重新组装，形成了一种新型的三明治型催化复合材料MnTAPP@bir。通过X射线衍射（XRD）、傅里叶变换红外光谱（FTIR）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）、热重分析（TGA）和布鲁诺尔-埃米特分析（BET）对该复合材料的结构和化学性质进行了表征。电催化研究表明，与水钠锰矿相比，MnTAPP@bir在10 mA cm时的析氧过电位为450 mV，塔菲尔斜率为121.5 mV dec，而水钠锰矿在10 mA cm时的析氧过电位为700 mV，塔菲尔斜率为230 mV dec。阻抗谱结果表明，MnTAPP@bir的电荷转移电阻明显低于水钠锰矿，这表明层间的MnTAPP提高了水钠锰矿的导电性。通过计时电流法测试，这种新材料在4000 s内也表现出优异的稳定性。
