Mg-doped SrTiO₃ photocatalyst with Ag-Co cocatalyst for enhanced selective conversion of CO₂ to CO using H₂O as the electron donor

Photocatalytic conversion of CO₂ by H₂O is a promising method for solving energy and environmental problems. In this context, efficient photocatalysts that facilitate the selective conversion of CO₂ to the value-added chemical CO are essential. In this study, for the first time in the literature, we used an Mg-doped SrTiO₃ photocatalyst (Mg–SrTiO₃) for the photocatalytic conversion of CO₂ to CO using H₂O as the electron donor under monochromatic UV-light irradiation at 365 nm. Compared to pristine SrTiO₃, Mg–SrTiO₃, which was prepared via a flux method, exhibited dramatically enhanced conversion of CO₂ to CO in the presence of an Ag–Co cocatalyst. Moreover, the selectivity toward CO evolution was >99%, which indicates suppression of the unnecessary and competitive H₂ evolution. Scanning electron microscopy of Mg–SrTiO₃ revealed edge-shaved cubic particles, which were correlated to the anisotropic distribution of photogenerated electrons and holes and the consequent enhancement of photocatalytic activity. Furthermore, the Mg-doping temperature and amount used to prepare Mg–SrTiO₃ influenced the substitution of Ti⁴⁺ sites by Mg²⁺ in the bulk of SrTiO₃, thereby affecting the CO evolution. The apparent quantum efficiency of optimal Mg–SrTiO₃ in the photocatalytic conversion of CO₂ was determined to be 0.05%

炭素―炭素結合形成のための酸化チタン光触媒反応に関する研究

京都大学新制・課程博士博士(人間・環境学)甲第23977号人博第1029号新制||人||242(附属図書館)2022||人博||1029(吉田南総合図書館)京都大学大学院人間・環境学研究科相関環境学専攻(主査)教授 吉田 寿雄, 教授 藤田 健一, 教授 小松 直樹学位規則第4条第1項該当Doctor of Human and Environmental StudiesKyoto UniversityDFA

Visible-light photoexcitation of pyridine surface complex, leading to selective dehydrogenative cross-coupling with cyclohexane

Upon photoirradiation with visible light, a pyridine molecule adsorbed on a TiO₂ surface can be photoexcited to give a pyridine radical cation via ligand-to-metal charge transfer (LMCT) between pyridine and titanium. This leads to dehydrogenative cross-coupling (DCC) between pyridine and cyclohexane with concomitant hydrogen evolution. Since the radical cation can selectively oxidize cyclohexane to a cyclohexyl radical, the cross-coupling between pyridine and cyclohexane proceeds with higher selectivity compared with that in photocatalysis by TiO₂ under UV irradiation

Mg-doped SrTiO3 Photocatalyst with Ag-Co Cocatalyst for Enhanced Selective Conversion of CO2 to CO Using H2O as the Electron Donor

Photocatalytic conversion of CO2 by H2O is a promising method for solving energy and environmental problems. In this context, efficient photocatalysts that facilitate the selective conversion of CO2 to the value-added chemical CO are essential. In this study, for the first time in the literature, we used an Mg-doped SrTiO3 photocatalyst (Mg-SrTiO3) for the photocatalytic conversion of CO2 to CO using H2O as the electron donor under monochromatic UV-light irradiation at 365 nm. Compared to pristine SrTiO3, Mg-SrTiO3, which is prepared via a flux method, exhibited dramatically enhanced conversion of CO2 to CO in the presence of Ag-Co cocatalyst. Moreover, the selectivity toward CO evolution was greater than 99%, indicating suppression of the unnecessary and competitive H2 evolution. Scanning electron microscopy of Mg-SrTiO3 revealed edge-shaved cubic particles, which were correlated to the anisotropic distribution of photogenerated electrons and holes and the consequent enhancement of photocatalytic activity. Furthermore, the Mg-doping temperature and amount used to prepare Mg-SrTiO3 influenced the substitution of Ti4+ sites in the bulk of SrTiO3 by Mg2+, thereby affecting the CO evolution. The apparent quantum efficiency of optimal Mg-SrTiO3 in the photocatalytic conversion of CO2 was determined to be 0.05%

AgFe dual cocatalyst for selective conversion of CO2 using K2YTa5O15 photocatalyst

The photocatalytic conversion of CO2 is a promising technique for realising a carbon neutral society based on the use of renewable energy sources. The application of dual cocatalysts consisting of AgCo and AgFe significantly improves the photocatalytic activity of an Al−SrTiO3 photocatalyst for the conversion of CO2 to CO in water. In this work, the photocatalytic conversion of CO2 using Ga2O3 and K2YTa5O15 photocatalysts was successfully performed in the presence of a AgFe dual cocatalyst loaded by a photodeposition method. The addition of Fe species to Ag/K2YTa5O15 was found to simultaneously increase the CO formation rate and the selectivity towards CO