Tetraphenylanthraquinone and Dihydroxybenzene-Tethered Conjugated Microporous Polymer for Enhanced CO2 Uptake and Supercapacitive Energy Storage

Abstract

Conjugated microporous polymers (CMPs) feature extended excellent porosity properties and fully conjugated electronic systems, making them highly effective for several uses, including photocatalysis, dye adsorption, CO₂ capture, supercapacitors, and so on. These polymers are known for their high specific surface area and adjustable porosity. To synthesize DHTP-CMPs (specifically TPE-DHTP CMP and Anthra-DHTP CMP) with abundant nitrogen (N) and oxygen (O) adsorption sites and spherical structures, we employed a straightforward Schiff-base [4 + 2] condensation reaction. This involved using 2,5-dihydroxyterephthalaldehyde (DHTP-2CHO) as the primary building block and phenolic OH group source, along with two distinct structures: 4,4′,4″,4”’-(ethene-1,1,2,2-tetrayl)tetraaniline (TPE-4NH₂) and 4,4′,4″,4”’-(anthracene-9,10-diylidenebis(methanediylylidene))tetraaniline (Anthra-4Ph-4NH₂). The synthesized Anthra-DHTP CMP had a remarkable BET surface area (BET_SA) of 431 m² g^–1. Additionally, it exhibited outstanding thermal stability, as shown by a T_d10 of 505 °C. Furthermore, for practical implementation, the Anthra-DHTP CMP demonstrates a significant capacity for capturing CO₂, measuring 1.85 mmol g^–1 at a temperature of 273 K and 1 bar. In a three-electrode test, the Anthra-DHTP CMP has a remarkable specific capacitance of 121 F g^–1 at 0.5 A g^–1. Furthermore, even after undergoing 5000 cycles, it maintains a capacitance retention rate of 79%. Due to their outstanding pore characteristics, abundant N and O, and conjugation properties, this Anthtra-DHTP CMP holds significant potential for CO₂ capture and supercapacitor applications. This work will pave the way for the development of materials based on DHTP-CMPs and their postmodification with additional groups, facilitating their use in photocatalysis, photodegradation, lithium battery applications, and so on.