核壳型SiO_(2)@Cu-TiO_(2)@SiO_(2)催化剂用于CO_(2)羧化反应研究

Core-shell SiO_(2)@Cu-TiO_(2)@SiO_(2) catalysts toward CO_(2) carboxylation reactions

针对Cu基纳米颗粒作为活性组分催化CO_(2)与末端炔烃反应制备丙炔酸类产品中存在的端炔自偶联副反应和转化率低等问题,本研究开发了一种“外壳层保护”策略,设计并制备了低Cu负载量的SiO_(2)@Cu-TiO_(2)@SiO_(2)催化剂.外层SiO_(2)壳可以保护TiO_(2)在煅烧过程中形成稳定的锐钛矿晶相,此外,煅烧过程中形成的孔结构在催化过程中可以通过空间限域作用有效抑制偶联副反应.通过优化,800℃煅烧得到的SiO_(2)@Cu-TiO_(2)@SiO_(2)催化剂在常压CO_(2)气氛中,苯丙炔酸产率达82.4%.本研究为炔酸类所需的非贵金属纳米催化剂的设计与合成提供了新的思路与方法.

As for the Cu-based heterogeneous catalysts toward CO_(2) carboxylation reactions,there exist self-coupling reaction of end-alkyne and low conversion toward alkyne acid.In this study,an“outer-shell layer protection”strategy was developed to synthesize the SiO_(2)@Cu-TiO_(2)@SiO_(2) catalysts with low loading amount of Cu species.The SiO_(2) outer layer can promote the formation of anatase TiO_(2) during the calcination process.Meanwhile,there were abundant pore formed within the SiO_(2) layer during the calcination process.The as-formed pores could effectively inhibit the selfcoupling reactions of end-alkyne through the spatial limiting effect.More importantly,under the optimal conditions,a yield of 82.4% was achieved for the phenylpropionic acid catalyzed by the as-developed SiO_(2)@Cu-TiO_(2)@SiO_(2) catalysts.Our findings will guide the design and syntheses of non-precious metal heterogeneous catalysts for CO_(2) utilization.