A Triple Tandem Reaction for the Upcycling of Products from Poorly Selective CO2 Photoreduction Systems

Low-selective CO 2 photoreduction systems are often overlooked in research, because the resulting mixed products are difficult to use in further reactions. In particular, the reutilization of gaseous hybrid products (such as CO and H 2 ), which are often mixed with incompletely converted CO 2 , is difficult. Here we design and construct two highly active cluster-based catalysts, Ni 5 W 10 and Ni 6 W 10 , which can be utilized in an efficient triple tandem reaction composed of low-selective CO 2 photoreduction, alkyne semi-hydrogenation and carbonylation reactions. The triple tandem system can sequentially convert the H 2 and CO mixture into high-value olefins and carbonyls, with an atomic utilization efficiency of up to 94%. In situ one-pot coupling of low-selective CO 2 photoreduction with alkyne semi-hydrogenation promotes the overall photoconversion efficiency (up to 1,425.0 μmol g −1 h −1 ), CO selectivity (from 50.8% to 80.0%) and alkyne-to-olefin transformation (conversion >86.0%, selectivity ~100.0%). Subsequently, the purified CO can be converted to different types of carbonylated product (CO conversion between 51% and 99%).