Laboratoire de Physique de l'Etat Condensé, UMR CNRS 6087, Université du Maine, 72085 Le Mans Cedex 09, France.
J Phys Chem B. 2010 Apr 8;114(13):4424-31. doi: 10.1021/jp911357v.
EPR investigations of the photoreduction of Ti(4+) into Ti(3+) under UV irradiation were carried out on three titanium-based materials for which the initial concentration of Ti(4+) was defined in the ternary phase diagram (TiOCl(2), H(2)O, DMF). The kinetics of this photoreduction was monitored at 200 K and related to the initial concentration of Ti(4+) in the solution. This study was complemented by a multi-approach EPR method (pulsed electron paramagnetic resonance (EPR), pulsed electron nuclear double resonance, and hyperfine sublevel correlation spectroscopy (HYSCORE)) with the aim of probing the proton environment of the Ti(3+) ions. Indeed, many species such as H(2)O, OH(-), HCOO(-) are located in the immediate vicinity of Ti(3+). Although we found that a distribution of g tensors was involved, for simplicity, two types of g tensor were used to describe the main features of the EPR signal related to the paramagnetic ions. Additionally, we have evidenced that two kinds of protons are identified next to Ti(3+) species, with specific distances determined from the hyperfine coupling parameters obtained by the HYSCORE method.
在三种钛基材料上进行了紫外线照射下 Ti(4+)光还原为 Ti(3+)的 EPR 研究，这些材料的 Ti(4+)初始浓度在三元相图（TiOCl(2)、H(2)O、DMF）中确定。在 200 K 下监测了这种光还原的动力学，并将其与溶液中 Ti(4+)的初始浓度相关联。这项研究还采用了多种 EPR 方法（脉冲电子顺磁共振（EPR）、脉冲电子-核双共振和超精细亚层相关光谱（HYSCORE））进行补充，目的是探测 Ti(3+)离子的质子环境。事实上，许多物质，如 H(2)O、OH(-)、HCOO(-)，都位于 Ti(3+)的附近。尽管我们发现涉及到 g 张量的分布，但为了简单起见，我们使用了两种类型的 g 张量来描述与顺磁离子相关的 EPR 信号的主要特征。此外，我们已经证明，在 Ti(3+)物种的附近鉴定出了两种类型的质子，通过 HYSCORE 方法获得的超精细耦合参数确定了它们的特定距离。
