Idígoras Jesús, Anta Juan A, Berger Thomas
Departamento de Sistemas Físicos, Químicos y Naturales, Área de Química Física, Universidad Pablo de Olavide, Ctra. Utrera, km 1, E-41013 Sevilla, Spain.
Department of Chemistry and Physics of Materials, University of Salzburg, Hellbrunnerstraße 34/III, A-5020 Salzburg, Austria.
J Phys Chem C Nanomater Interfaces. 2016 Dec 15;120:27882-27894. doi: 10.1021/acs.jpcc.6b09926. Epub 2016 Dec 7.
Some material properties depend not only on synthesis and processing parameters, but may furthermore significantly change during operation. This is particularly true for high surface area materials. We used a combined electrochemical and spectroscopic approach to follow the changes of the photoelectrocatalytic activity and of the electronic semiconductor properties of mesoporous TiO films upon charge transfer reductive doping. Shallow donors (i.e. electron/proton pairs) were introduced into the semiconductor by the application of an external potential or, alternatively, by band gap excitation at open circuit conditions. In the latter case the effective open circuit doping potential depends critically on electrolyte composition (e.g. the presence of electron or hole acceptors). Transient charge accumulation (electrons and protons) in nanoparticle electrodes results in a photocurrent enhancement which is attributed to the deactivation of recombination centers. In nanotube electrodes the formation of a space charge layer results in an additional decrease of charge recombination at positive potentials. Doping is transient in nanoparticle films, but turns out to be stable for nanotube arrays.
一些材料特性不仅取决于合成和加工参数，而且在运行过程中可能会发生显著变化。对于高比表面积材料而言尤其如此。我们采用电化学和光谱学相结合的方法，来跟踪介孔TiO薄膜在电荷转移还原掺杂后光催化活性和电子半导体特性的变化。通过施加外部电势，或者在开路条件下通过带隙激发，将浅施主（即电子/质子对）引入半导体。在后一种情况下，有效的开路掺杂电势严重依赖于电解质组成（例如电子或空穴受体的存在）。纳米颗粒电极中的瞬态电荷积累（电子和质子）导致光电流增强，这归因于复合中心的失活。在纳米管电极中，空间电荷层的形成导致在正电势下电荷复合的进一步减少。掺杂在纳米颗粒薄膜中是瞬态的，但对于纳米管阵列来说却是稳定的。
