Applied Catalysis A: General ( IF 5.5 ) Pub Date : 2017-08-25 , DOI: 10.1016/j.apcata.2017.08.031 Mohamed Mokhtar Mohamed , M. Khairy , Salah Eid
Silver nanoparticles successfully incorporated in titanate nanosheets and synthesized hydrothermally via employing cetyltrimethylammonium bromide (CTAB) and triblock copolymer (pluronic F127) assisted templates were thoroughly characterized using transmission electron microscopy-selected area electron diffraction (TEM-SAED), X-ray diffraction, diffuse reflectance UV/visible absorption spectroscopy, N2 sorptiometry, FTIR and Raman spectroscopy. The dispersed Ag nanoparticles of uniform size (2–3 nm) were found to contact intimately with titanateF127 nanosheets to show superior crystallinity, wider layer distances and higher surface area and pore volume (SBET = 51.1 m2 g−1, Vp = 0.081 cm3g−1) than Ag/titanateCTAB (7.2 m2 g−1, 0.02 cm3 g−1). This constructed Ag/titanateF127 exhibits markedly improved electrocatalytic (1.4-fold) and photoelectrocatalytic (4.0-fold) activities and stabilities towards methanol oxidation than that of Ag/titanateCTAB; as determined using cyclic voltammetry, linear sweep voltammetry and chronoamperometry. The enhanced activity of Ag/titanateF127 was also attributed to electron transfer across the interface potential of the composite Ag-titanateF127 as well as the delay of charge recombination that has been substantiated not only via exposed Ag but also through the non-decomposed carbon template. This enhanced electron transfer and electronic conductivity was established by impedance spectroscopy, and exhibits the maximum obtained photocurrent density (2.0 mA cm−2) under visible light illumination (λ > 420 nm, 88 W). The results revealed that the template F127 had a significant effect not only on enhancing the titanate crystallinity and exhibiting a surface plasmon resonance band; unlike Ag/titanateCTAB, but also in acquiring a high pore volume value and widened layers, which all work towards improving the Ag-titanateF127 durability for methanol oxidation.
中文翻译:
表面活性剂辅助的钛酸银的形成作为甲醇电氧化的活性催化剂
使用透射电子显微镜选择区域电子衍射(TEM-SAED),X射线衍射,扩散法对通过成功地掺入钛酸酯纳米片中并通过十六烷基三甲基溴化铵(CTAB)和三嵌段共聚物(pluronic F127)辅助模板水热合成的银纳米颗粒进行了全面表征反射率紫外/可见吸收光谱,N 2吸收法,FTIR和拉曼光谱。发现均匀大小(2-3 nm)的分散的Ag纳米颗粒与钛酸酯F127纳米片紧密接触,显示出优异的结晶度,更宽的层距以及更高的表面积和孔体积(S BET = 51.1 m 2 g -1,V p =0.081厘米3克-1)比的Ag /钛酸CTAB(7.2米2 克-1,0.02厘米3 克-1)。这种构造的Ag /钛酸酯F127与Ag /钛酸酯CTAB相比,具有显着改善的电催化活性(1.4倍)和光电催化活性(4.0倍)以及对甲醇氧化的稳定性;用循环伏安法,线性扫描伏安法和计时电流法测定。Ag /钛酸酯F127的增强活性还归因于电子穿过复合Ag-钛酸酯F127的界面电势以及不仅通过暴露的银而且通过未分解的碳模板证实的电荷重组延迟。这种增强的电子传递和电子传导性通过阻抗光谱法建立,并且在可见光照明(λ> 420 nm,88 W)下表现出最大的光电流密度(2.0 mA cm -2)。结果表明,模板F127不仅对增强钛酸盐的结晶度和表现出表面等离振子共振带具有显著作用。与Ag /钛酸酯CTAB不同,它还具有较高的孔体积值和更宽的涂层,所有这些都有助于提高Ag-钛酸酯F127对甲醇氧化的耐久性。