Physical Chemistry Department, Faculty of Chemistry, University of Bucharest, Regina Elisabeta, No. 4-12, 030018 Bucharest, Romania.
"Ilie Murgulescu" Institute of Physical Chemistry, 202 Splaiul Independentei, 060021 Bucharest, Romania.
Int J Mol Sci. 2022 Nov 25;23(23):14703. doi: 10.3390/ijms232314703.
The properties of newly synthesized CuO/CuO-decorated TiO/graphene oxide (GO) nanocomposites (NC) were analyzed aiming to obtain insight into their photocatalytic behavior and their various applications, including water remediation, self-cleaning surfaces, antibacterial materials, and electrochemical sensors. The physico-chemical methods of research were photoluminescence (PL), electron paramagnetic resonance (EPR) spectroscopy, cyclic voltammetry (CV), and differential pulse voltammetry (DPV). The solid samples evidenced an EPR signal that can be attributed to the oxygen-vacancy defects and copper ions in correlation with PL results. Free radicals generated before and after UV-Vis irradiation of powders and aqueous dispersions of CuO/CuO-decorated TiO/GO nanocomposites were studied by EPR spectroscopy using two spin traps, DMPO (5,5-dimethyl-1-pyrroline-N-oxide) and CPH (1-hydroxy-3-carboxy-2,2,5,5-tetramethylpyrrolidine), to highlight the formation of hydroxyl and superoxide reactive oxygen species, respectively. The electrochemical characterization of the NC modified carbon-paste electrodes (CPE) was carried out by CV and DPV. As such, modified carbon-paste electrodes were prepared by mixing carbon paste with copper oxides-decorated TiO/GO nanocomposites. We have shown that GO reduces the recombination process in TiO by immediate electron transfer from excited TiO to GO sheets. The results suggest that differences in the PL, respectively, EPR data and electrochemical behavior, are due to the different copper oxides and GO content, presenting new perspectives of materials functionalization.
新合成的 CuO/CuO 修饰的 TiO/氧化石墨烯（GO）纳米复合材料（NC）的性质进行了分析，旨在深入了解其光催化行为及其在水修复、自清洁表面、抗菌材料和电化学传感器等方面的各种应用。研究采用了光致发光（PL）、电子顺磁共振（EPR）光谱、循环伏安法（CV）和差分脉冲伏安法（DPV）等物理化学方法。固体样品的 EPR 信号可以归因于氧空位缺陷和与 PL 结果相关的铜离子。通过 EPR 光谱使用两种自旋捕获剂 DMPO（5,5-二甲基-1-吡咯啉-N-氧化物）和 CPH（1-羟基-3-羧基-2,2,5,5-四甲基吡咯烷）研究了粉末和 CuO/CuO 修饰的 TiO/GO 纳米复合材料水分散体在 UV-Vis 辐照前后产生的自由基，以分别突出羟基和超氧自由基活性氧物质的形成。通过 CV 和 DPV 对 NC 修饰的碳糊电极（CPE）进行了电化学表征。通过将碳糊与氧化铜修饰的 TiO/GO 纳米复合材料混合，制备了修饰的碳糊电极。我们已经表明，GO 通过将激发态 TiO 中的电子立即转移到 GO 片上，减少了 TiO 中的复合过程。结果表明，PL、EPR 数据和电化学行为的差异是由于不同的氧化铜和 GO 含量所致，为材料功能化提供了新的视角。
