Photoreduction of nitroaromatics into amines with TiO₂ (P25) via greener method has attracted a great deal of interest. Generally, this reaction is feasible as the reduction potential of nitro groups (-0.5 eV) lies below the conduction band (-0.85 eV vs. NHE) of TiO₂. However, functional groups such as nitrile (-CN), azido (-N₃), aceto (-CH₃CO), etc. are generally not photoreduced by conventional P25 due to their unfavorable reduction potential relative to titania. This report demonstrates efficient photocatalytic reduction of aromatic nitriles by tuning the band energies of Cu-TiO₂ nanostructures of different morphologies. The band energetics were determined by optical and electrochemical studies which revealed that Cu loaded titania nanotubes (Cu-TNT) possess more negative conduction band gap (-2.7 eV vs. vacuum) energy as compared to LUMO level of benzonitrile (-2.82 eV). This factor has probably facilitated better reduction efficiency of benzonitrile (> 90%) and its derivatives with Cu-TNT in comparison to almost no reactivity with Cu-P25 under similar conditions. In addition to suitable conduction band position of Cu-TNT, presence of anatase phase and higher surface area (204 m²/g) might have enhanced the reaction rate.

TiO ₂（P25）通过更绿色的方法将硝基芳族化合物光还原为胺引起了人们的极大兴趣。通常，该反应是可行的，因为硝基的还原电位（-0.5 eV）低于TiO ₂的导带（-NHE相对于-0.85 eV）。然而，由于相对于二氧化钛不利的还原潜力，常规P25通常不将诸如腈（-CN），叠氮基（-N ₃），乙酰基（-CH ₃ CO）等的官能团光还原。该报告证明了通过调节Cu-TiO _2的能带可以有效地光催化还原芳香腈不同形态的纳米结构。通过光学和电化学研究确定了能带能量，结果表明，与苯甲腈的LUMO能级（-2.82 eV）相比，负载铜的二氧化钛纳米管（Cu-TNT）具有更多的负导电带隙（-2.7 eV对真空）能。与在相似条件下几乎不与Cu-P25发生反应相比，该因素可能促进了更好的苄腈（> 90％）及其衍生物与Cu-TNT的还原效率。除了合适的Cu-TNT导带位置外，锐钛矿相和更高的表面积（204 m ² / g）的存在可能会提高反应速率。