Gupta Satyajit, De Leon Luis, Subramanian Vaidyanathan Ravi
Department of Chemical and Materials Engineering, University of Nevada, Reno, NV 89557, USA.
Phys Chem Chem Phys. 2014 Jul 7;16(25):12719-27. doi: 10.1039/c3cp55439b.
In this study, a hydrogen generation photocatalyst based on bismuth titanate (Bi2Ti2O7 - BTO) modified with manganese (Mn) has been developed. Mn of varying weight percent was added to construct a modified BTO catalyst (Mn_BTO), in order to enhance the opto-electronic and photocatalytic hydrogen generation capabilities of the pristine BTO. The structural, morphological, and optical properties of the photocatalysts were evaluated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and UV-visible spectrophotometry. The XRD, SEM, and TEM analyses indicate the formation of the pyrochlore BTO phase with particles of dimensions 30 ± 10 nm. The UV-visible study revealed a reduction in the bandgap of Mn_BTO and enhanced absorption in the visible range, compared to the pristine BTO. The catalyst was optimized for maximum hydrogen generation from a water-methanol (sacrificial electron donor) system in a slurry reactor. The photocatalytic hydrogen evolution studies indicate that the Mn_BTO with up to 1 wt% Mn facilitates an optimal 140% increase in the hydrogen yield. The role of formic acid and formaldehyde as additives in photocatalytic hydrogen evolution has also been examined. The effect of Mn content, mechanistic overview, and reusability of the catalyst are discussed.
在本研究中，开发了一种基于用锰（Mn）改性的钛酸铋（Bi2Ti2O7 - BTO）的产氢光催化剂。添加不同重量百分比的Mn以构建改性的BTO催化剂（Mn_BTO），以增强原始BTO的光电和光催化产氢能力。通过X射线衍射（XRD）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）和紫外-可见分光光度法对光催化剂的结构、形态和光学性质进行了评估。XRD、SEM和TEM分析表明形成了尺寸为30±10 nm的颗粒的烧绿石BTO相。紫外-可见研究表明，与原始BTO相比，Mn_BTO的带隙减小，在可见光范围内的吸收增强。该催化剂在浆态反应器中针对从水-甲醇（牺牲电子供体）体系中最大程度产氢进行了优化。光催化析氢研究表明，Mn含量高达1 wt%的Mn_BTO使产氢量最佳地提高了140%。还研究了甲酸和甲醛作为添加剂在光催化析氢中的作用。讨论了Mn含量的影响、机理概述以及催化剂的可重复使用性。
