Simultaneous CO₂ and NO Conversion by Spatially Locating Dual Photocatalytic Sites on a Microporous Polymer

Direct photocatalytic recycling of CO₂ from practical exhaust gas is highly desirable but challenged by the competitive O₂ reduction and coexisting NO pollutant. O₂ as an inevitable component seriously suppresses CO₂ reduction while being essential for photocatalytic NO removal. Herein, we introduce a SiO₂-templated porphyrin-based polymer (STP) for integrating Pd(II) sites toward selective CO₂ reduction and assembling TiO₂ nanoparticles as NO oxidation sites. The TiO₂-mediated electron transfer process facilitates the charge separation at the spatially separated Pd(II) and TiO₂ sites. The O₂ effect can be balanced between CO₂ reduction and NO oxidation to achieve remarkable efficiency for CO₂ reduction (2.8 mmol g^-1 h^-1) and NO removal (50.6%) in simulated flue gas under visible-light irradiation. In contrast, CO₂ reduction is almost completely inhibited on Pd/TiO₂ without the STP layer. Further, the reaction mechanism reveals the parallel pathways of selective CO₂ reduction and NO oxidation on the designed TiO₂/Pd-STP composite. This study demonstrates a feasible strategy for building dual active sites into CO₂-affinitive polymers capable of simultaneous carbon recycling and pollution abatement in practical environments.