Photocatalytic Stille Cross-coupling on Gold/g-C 3 N 4 Nano-heterojunction
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doi: 10.1007/s40242-020-0229-5
Article
Photocatalytic Stille Cross-coupling on Gold/g-C3N4 Nano-heterojunction YU Qiuying, LIN Xiu, LI Xinhao * and CHEN Jiesheng School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, P. R. China Abstract Heterogeneous catalysts have been developed for C―C coupling reactions, but stand low activity and always proceed under harsh conditions. Photocatalytic Stille cross-coupling reaction as a green catalytic method for C―C bond formation is of great interest for a wide range of scientists but still lacks stable and highly efficient cat alysts. Herein, we have designed an Au nanoparticle-graphitic carbon nitride heterojunction as an outstanding photocatalyst for artificial photosynthesis in Stille cross-coupling reaction. The interface effect between metal and semiconductor makes electron rectify and prevents the recombination of electron-hole pairs. Moreover, the efficiency of Au nanoparticle catalysts could be adjusted by gold contents. Thus the turnover frequency(TOF) value reached the highest level of 788 h −1 over the optimal heterojunction catalyst. Most importantly, the C―C bond formation reaction has been proved to be carried out well under visible light irradiation, indicating the low-cost organic synthesis process. Further analysis confirmed the stability and general application of our heterogeneous Au nano -heterojunction catalyst. Keywords Photocatalysis; Stille coupling reaction; Green chemistry; Interface effect
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Introduction
Gold nanoparticle catalysts have been widely developed for decades as efficient, easily-obtained and non-toxicity noble metal heterogeneous catalysts[1―5]. Au nanoparticle catalysts show excellent photo-activity and are always considered as a promising photocatalyst for organic synthesis[6]. Graphitic carbon nitride(g-C3N4) applied as a light-responsive and low-cost semiconductor support has been researched widely in the area of photocatalysis[7,8], but the low activity caused by quick recombination of electron-hole pairs has limited its application[9]. The construction of Au nanoparticles on g-C3N4 support has also attracted numerous attention for organic degradation[10], CO2 photocatalysis reduction[11], water splitting[12] and fuel production[13]. However, the application of Au nanoparticles supported on g-C3N4 as catalysts or photocatalysts for organic C―C coupling reactions has been rarely touched because of the relatively low catalytic efficiency of Au nanoparticles as compared with the widely used Pd catalysts. Stille cross-coupling reaction as an efficient chemical synthesis reaction for C―C coupling among other conventional palladium-catalysed coupling reactions(such as Suzuki coupling and Heck coupling) is always not popular for Au catalysts[14―18]. Current studies of gold-catalysed cross-coupling reactions still focus on the thermal catalysis system under harsh conditions. However, visible-light-initiated artificial photo-synthesis is a green and low-cost method for organic synthe-
sis, which i
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