Hollow microtubular chalcogen derived conjugated organic polymers for CO2 photoreduction: Morphology regulation and electron delocalization refining via atom substitution

The design of high-performance organic photocatalysts with special morphologies via subtle engineering at the atomic level is difficult. In this study, a sequence of hollow microtubular chalcogen (O, S, Se, and Te) conjugated organic polymers (COPs) for CO2 photoreduction was successfully synthesized for the first time. The introduction of chalcogen atoms into molecular skeletons can regulate the flexibility of the building blocks, drive the polymerization of materials to evolve into a hollow tube morphology and significantly modify the energy band. The Se and Te atoms as semimetal elements, introduced in the organic molecules, distinctly boost the delocalization degree of excited electrons and accelerate the charge separation. The Se, Te-COPs show high photocatalytic CO2-to-CO conversion activity, namely 233.4, 347.3 μmol·g−1 in 6 h and 0.42 %, 0.67 % apparent quantum yield at 365 nm, respectively. This study presents the possibility of exploiting high-activity organic photocatalysts with special morphologies via a atom substitution strategy. [Display omitted] •A series of hollow microtubular chalcogen-COPs was synthesized for the first time.•The flexibility of chalcogen-bridged monomers derived the morphology evolution.•The semi-metals characteristics of Se and Te were introduced into organic photocatalytic reaction for the first time.•Se, Te-COPs distinctly excited more active electrons and promote electrons delocalization.•Fs-TAS and DFT confirmed the ultrafast charge transfer and lower energy barrier (*CO → COOH*) for Se, Te-COPs.