Photochemical Reduction of Low Concentrations of CO 2 in a Porous Coordination Polymer with a Ruthenium(II)–CO Complex

Abstract Direct use of low pressures of CO 2 as a C1 source without concentration from gas mixtures is of great interest from an energy‐saving viewpoint. Porous heterogeneous catalysts containing both adsorption and catalytically active sites are promising candidates for such applications. Here, we report a porous coordination polymer (PCP)‐based catalyst, PCP‐Ru II composite, bearing a Ru II ‐CO complex active for CO 2 reduction. The PCP‐Ru II composite showed improved CO 2 adsorption behavior at ambient temperature. In the photochemical reduction of CO 2 the PCP‐Ru II composite produced CO, HCOOH, and H 2 . Catalytic activity was comparable with the corresponding homogeneous Ru II catalyst and ranks among the highest of known PCP‐based catalysts. Furthermore, catalytic activity was maintained even under a 5 % CO 2 /Ar gas mixture, revealing a synergistic effect between the adsorption and catalytically active sites within the PCP‐Ru II composite.