Tweaking Photo CO<sub>2</sub> Reduction by Altering Lewis Acidic Sites in Metalated‐Porous Organic Polymer for Adjustable H<sub>2</sub>/CO Ratio in Syngas Production
Ratul Paul, Risov Das, Nitumani Das, Subhajit Chakraborty, Chih‐Wen Pao, Quang Thang Trịnh, G. T. Kasun Kalhara Gunasooriya, John Mondal, Sebastian C. Peter
Abstract
Abstract Herein, we have specifically designed two metalated porous organic polymers ( Zn‐POP and Co‐POP ) for syngas (CO+H 2 ) production from gaseous CO 2 . The variable H 2 /CO ratio of syngas with the highest efficiency was produced in water medium (without an organic hole scavenger and photosensitizer) by utilizing the basic principle of Lewis acid/base chemistry. Also, we observed the formation of entirely different major products during photocatalytic CO 2 reduction and water splitting with the help of the two catalysts, where CO (145.65 μmol g −1 h −1 ) and H 2 (434.7 μmol g −1 h −1 ) production were preferentially obtained over Co‐POP & Zn‐POP , respectively. The higher electron density/better Lewis basic nature of Co‐POP was investigated further using XPS, XANES, and NH 3 ‐TPD studies, which considerably improve CO 2 activation capacity. Moreover, the structure–activity relationship was confirmed via in situ DRIFTS and DFT studies, which demonstrated the formation of COOH* intermediate along with the thermodynamic feasibility of CO 2 reduction over Co‐POP while water splitting occurred preferentially over Zn‐POP .