Facile Room Temperature Synthesis of Precious‐Metal‐Free Coordination Polymer Photocatalyst for Improved Visible‐Light CO2 Reduction

Abstract

The Pb–S‐based coordination polymer (CP), named KGF‐9, [Pb(tadt)]n (tadt = 1,3,4‐thiadiazole‐2,5‐dithiolate), can selectively convert CO2 into HCOO− (>99%) under visible light, with an apparent quantum yield (AQY) of 2.6% at 400 nm, without a cocatalyst. However, KGF‐9 is an intrinsically nonporous CP, and its small specific surface area (<1 m2 g−1) might hinder the realization of its full potential as a photocatalyst. Herein, facile synthetic routes at room temperature are reported through a solid‐state reaction and a liquid‐phase reaction (LPR) using lead(II) acetate as a precursor. The use of lead(II) acetate promotes the deprotonation of the H2tadt ligand, resulting in a faster coordination reaction, a reduced feature size, and a drastic increase in specific surface area (≈10 m2 g−1). A higher AQY for formate production (5.9% at 400 nm) is found for KGF‐9 prepared via a 60 min LPR. The improved photocatalytic activity of the LPR sample is attributed to the presence of long‐lived charge carriers, which is revealed by time‐resolved microwave conductivity measurements. The results of this study provide a simple but effective strategy toward increasing the activity of CP‐based photocatalysts.