Efficient non-volatile organogold complex for TiO2-supported gold cluster catalysts: Preparation and catalytic activity for CO oxidation

• Published in: Journal of catalysis 2022-04, Vol.408, p.236-244
• Main Authors: Xuan Dien, Luong, Murayama, Toru, Tuan Hung, Nguyen, Duc Truong, Quang, Dang Chinh, Huynh, Yoshimura, Masamichi, Haruta, Masatake, Ishida, Tamao
• Format: Article
• Language: English
• Subjects: CO oxidation; Gold clusters; Gold nanoparticles; Solid grinding
• ISSN: 0021-9517
• DOI: 10.1016/j.jcat.2022.03.008

[Display omitted] •Au/TiO2 was prepared by solid grinding using a non-volatile organogold complex.•Addition of base facilitated decomposition of the Au complex to give Au clusters.•The Au complex was stabilized on TiO2 efficiently by hydrogen bonding.•The catalyst showed higher catalytic activity for CO oxidation than conventional one. Gold nanoparticles supported on titania (Au/TiO2) catalysts were prepared by solid grinding (SG) method using a halide-free nonvolatile organogold complex, bis(phenyl)boroxinato(4-tolylpyridyl)gold(III), abbreviated as AuBO, followed by calcination. Density functional theory (DFT) calculation revealed that AuBO was adsorbed on TiO2 by hydrogen bonding with the surface hydroxy group of TiO2 and that the adsorption energy was lower than those of other gold precursors. The obtained catalyst (AuBO/TiO2) showed higher catalytic activity for CO oxidation than did Au/TiO2 prepared by conventional deposition–precipitation method and by SG using other organogold complexes. Furthermore, grinding of the gold precursor with potassium tert-butoxide followed by calcination (AuBO/K-TiO2) improved the catalytic activity and 100% CO conversion reached at − 23 °C (temperature at which 50% CO conversion occurs, T1/2 =  − 39 °C) as compared to AuBO/TiO2 (T1/2 =  − 28 °C). Potassium tert-butoxide facilitated the decomposition of AuBO adsorbed on TiO2, and increased surface basicity contributed to the improved catalytic activity. AuBO/K-TiO2 also exhibited high catalyst stability for CO oxidation at room temperature.