Selective photocatalytic CO2 reduction to CH4 over metal-free porous polyimide in the solid–gas mode

Abstract

Using a catalyst-free one-pot polycondensation approach, a new donor–acceptor (D–A) based porous polyimide (PeTt–POP) photocatalyst was developed. PeTt–POP produced CH₄ (125.63 ppm g⁻¹ in 6 h) from CO₂ under visible light irradiation in the gas–solid mode without the use of co-catalysts or sacrificial agents. The progress of the reaction and the corresponding intermediate species involved in the CO₂ reduction were identified by operando DRIFTS experiments, from which a plausible reaction mechanism was proposed.