Bi^3+/5+ ions were incorporated into W⁶⁺ and N³⁻ doped TiO₂ by the sol–gel and hydrothermal reduction methods. The products obtained by these methods were different and were designated as BiWNT and Bi⁰-BiWNT, respectively. Bi was incorporated into the TiO₂ lattice by the sol–gel method and some of Bi was reduced to the Bi⁰ state on the surface of the catalyst in the hydrothermal method. The PXRD results confirmed the anatase phase for the BiWNT sample and mixed anatase and rutile phases for the Bi⁰-BiWNT sample. Incorporation of higher or lower valence metal/non-metal ions into the TiO₂ lattice is usually accompanied by the formation of neutral/ionized oxygen and titanium vacancies. An effective strategy is to monitor the inherently created defects/imperfections which can influence the properties such as the electronic structure, optical absorption, charge transport mechanism and surface acidity/basicity. Estimation of the Bi⁵⁺/Bi³⁺/Bi⁰ content in the BiWNT and Bi⁰-BiWNT samples was carried out by XPS analysis of Bi 4f_7/2 and 4f_5/2 spin states. The charge transfer process in the bicrystalline framework of Bi⁰-BiWNT depends on the positions of the energy levels within the band gap and it can be either the Type II heterojunction mechanism or the direct Z-scheme mechanism or it can be both of these mechanisms. Higher photocatalytic activity of the Bi⁰-metallised sample could be ascribed to various factors such as the bicrystalline framework of the lattice, presence of substitutional N, and surface plasmonic effect of Bi⁰ deposits, and to the unique defect chemistry of the sample.

中文翻译：

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通过水热还原法同步实现表面Bi0金属化和将Bi3 + / 5 +离子掺入W6 +，N3-掺杂的TiO2晶格中：表面等离振子共振效应可有效进行光催化

通过溶胶-凝胶法和水热还原法将Bi ^{3 + / 5 +}离子掺入W ⁶⁺和N ^3-掺杂的TiO _2中。通过这些方法获得的产物不同，分别称为BiWNT和Bi ⁰ -BiWNT。通过溶胶-凝胶法将Bi掺入TiO ₂晶格中，而在水热法中，某些Bi在催化剂表面还原为Bi ⁰态。PXRD结果确认了BiWNT样品的锐钛矿相和Bi ⁰ -BiWNT样品的锐钛矿相和金红石相。将较高或较低价态的金属/非金属离子掺入TiO _2中晶格通常伴随着中性/离子化氧和钛空位的形成。一种有效的策略是监视可能会影响诸如电子结构，光吸收，电荷传输机制和表面酸度/碱度等特性的内在缺陷。通过对Bi 4f _7/2和4f _5/2自旋态进行XPS分析，估算BiWNT和Bi ⁰ -BiWNT样品中Bi ⁵⁺ / Bi ³⁺ / Bi ^0的含量。Bi ⁰双晶构架中的电荷转移过程-BiWNT取决于带隙内能级的位置，它可以是II型异质结机制或直接Z方案机制，也可以是这两种机制。Bi ⁰金属化样品的较高光催化活性可归因于各种因素，例如晶格的双晶构架，取代N的存在和Bi ⁰沉积物的表面等离子体效应，以及样品的独特缺陷化学性质。