Simultaneous CO ₂ and NO Conversion by Spatially Locating Dual Photocatalytic Sites on a Microporous Polymer

Direct photocatalytic recycling of CO 2 from practical exhaust gas is highly desirable but challenged by the competitive O 2 reduction and coexisting NO pollutant. O 2 as an inevitable component seriously suppresses CO 2 reduction while being essential for photocatalytic NO removal. Herein, we introduce a SiO 2 -templated porphyrin-based polymer (STP) for integrating Pd(II) sites toward selective CO 2 reduction and assembling TiO 2 nanoparticles as NO oxidation sites. The TiO 2 -mediated electron transfer process facilitates the charge separation at the spatially separated Pd(II) and TiO 2 sites. The O 2 effect can be balanced between CO 2 reduction and NO oxidation to achieve remarkable efficiency for CO 2 reduction (2.8 mmol g –1 h –1 ) and NO removal (50.6%) in simulated flue gas under visible-light irradiation. In contrast, CO 2 reduction is almost completely inhibited on Pd/TiO 2 without the STP layer. Further, the reaction mechanism reveals the parallel pathways of selective CO 2 reduction and NO oxidation on the designed TiO 2 /Pd-STP composite. This study demonstrates a feasible strategy for building dual active sites into CO 2 -affinitive polymers capable of simultaneous carbon recycling and pollution abatement in practical environments.