Direct conversion of waste CO2 avoids CO2 capture and lowers the cost of CO2 utilisation; however, this route remains a challenging research topic. Developing catalysts that facilitate the enrichment and conversion of waste CO2 is therefore essential. Porous polymer catalysts offer unique advantages due to their high surface area and tunable functionality. These materials catalyse the conversion of both simulated waste CO2 and CO2 present in industrial waste gases, such as anaerobic fermentation gas, lime kiln waste gas, and coal-fired flue gas. This review summarises recent progress on the direct conversion of waste CO2 using porous polymer catalysts. It analyses the structural features of these catalysts, their CO2 adsorption properties, and the associated catalytic mechanisms. A quantitative comparison of catalytic performance—such as turnover frequency, stability, and CO2 adsorption capacity—is also provided. The findings may support the rational design and synthesis of catalysts for the direct utilisation of waste CO2, and provide parameters for the industrialisation of porous polymer catalysts.
