Ding Yuchen, Nagpal Prashant
Chemistry and Biochemistry, University of Colorado Boulder, Boulder, USA.
Phys Chem Chem Phys. 2017 Apr 12;19(15):10042-10050. doi: 10.1039/c7cp00774d.
Nanostructured titanium dioxide (TiO) has been intensively investigated as a material of choice for solar energy conversion in photocatalytic, photoelectrochemical, photovoltaic, and other photosensitized devices for converting light into chemical feedstocks or electricity. Towards management of light absorption in TiO, while the nanotubular structure improves light absorption and simultaneous charge transfer to mitigate problems due to the indirect bandgap of the semiconductor, typically dopants are used to improve light absorption of incident solar irradiation in the wide bandgap of TiO. While these dopants can be critical to the success of these solar energy conversion devices, their effect on photophysical and photoelectrochemical properties and detailed photokinetics are relatively under-studied. Here, we show the effect of deep and shallow metal dopants on the kinetics of photogenerated charged carriers in TiO and the resulting effect on photocatalytic and photoelectrochemical processes using these nanotube membranes. We performed a detailed optical, electronic, voltammetry and electrochemical impedance study to understand the effect of shallow and deep metal dopants (using undoped and niobium- and copper-doped TiO nanotubes) on light absorption, charge transport and charge transfer processes. Using wireless photocatalytic methylene blue degradation and carbon dioxide reduction, and wired photoelectrochemical device measurements, we elucidate the effect of different dopants on solar-to-fuel conversion efficiency and simultaneously describe the photokinetics using a model, to help design better energy conversion devices.
纳米结构的二氧化钛（TiO₂）作为光催化、光电化学、光伏及其他用于将光转化为化学原料或电能的光敏器件中太阳能转换的首选材料，已得到深入研究。为了控制TiO₂中的光吸收，虽然纳米管结构可改善光吸收并同时促进电荷转移以减轻因半导体间接带隙引起的问题，但通常会使用掺杂剂来提高TiO₂宽带隙中对入射太阳辐射的光吸收。虽然这些掺杂剂对这些太阳能转换器件的成功至关重要，但它们对光物理和光电化学性质以及详细光动力学的影响相对研究较少。在此，我们展示了深浅金属掺杂剂对TiO₂中光生带电载流子动力学的影响以及对使用这些纳米管膜的光催化和光电化学过程的影响。我们进行了详细的光学、电子、伏安法和电化学阻抗研究，以了解浅深金属掺杂剂（使用未掺杂以及铌和铜掺杂的TiO₂纳米管）对光吸收、电荷传输和电荷转移过程的影响。通过无线光催化亚甲基蓝降解和二氧化碳还原以及有线光电化学器件测量，我们阐明了不同掺杂剂对太阳能到燃料转换效率的影响，并同时使用模型描述光动力学，以帮助设计更好的能量转换器件。
