Photocatalytic CO₂ reduction is a technology that uses solar energy to convert carbon dioxide into useful fuels or chemicals, with its core lying in the choice of catalyst and the optimization of the reaction system. Depending on the phase of the reaction system, photocatalytic CO₂ reduction is mainly divided into gas-phase and liquid-phase types, each with its own characteristics and suitable application scenarios.
In liquid-phase photocatalytic CO₂ reduction, solid photocatalysts are uniformly dispersed in the solution and kept suspended by a magnetic stirrer to improve dispersion and reaction efficiency. The advantage of this method is its relatively simple operation, but it is limited by the low solubility of CO₂ in solution and by pH changes that affect reaction performance, so its application and development are somewhat constrained.
In contrast, gas-phase photocatalytic CO₂ reduction offers greater advantages. In this approach, the photocatalyst is placed on a platform inside the reactor and CO₂ gas fills the entire system. Because the diffusion coefficient of CO₂ in the gas phase is about four orders of magnitude higher than in the liquid phase, gas more easily contacts the catalyst and products desorb more readily, thereby improving reaction efficiency. Gas-phase reactions also avoid the hassle of catalyst separation and are more amenable to industrial scaling. Gas-phase reactions are further divided into thin-film gas–solid and fixed-bed gas–solid modes. The thin-film mode relies on passive diffusion, but mass transfer efficiency decreases as reactor thickness increases; the fixed-bed mode, by contrast, uses a through-flow gas design combined with an efficient circulation system to ensure full contact between CO₂ and the catalyst, significantly increasing conversion rates.
In practical applications, a variety of catalyst types are used, including metal oxides, sulfides, and composite materials; these materials absorb light to generate electron–hole pairs that drive CO₂ reduction reactions. Reaction products may include CO, CH₄, H₂, etc., depending on the catalyst and reaction conditions.
Professional equipment is essential for performing these experiments efficiently. For example, the Labsolar-6A all-glass automatic online trace gas analysis system is specifically designed for photocatalytic CO₂ reduction. It uses a highly gas-tight glass system and a magnet-driven piston pump to achieve rapid gas circulation and mixing, avoiding concentration gradient errors and ensuring experimental accuracy and reproducibility. The system supports atmospheric or slight negative pressure conditions and is compatible with multiple gas detection methods, making it an ideal tool for photocatalysis research. In addition, the company offers supporting products such as fiber-optic light sources, chromatographs, and reactors to form a complete solution that helps researchers optimize catalyst performance and reaction conditions, facilitating the transition of photocatalytic CO₂ reduction from the laboratory to industrial application.
In summary, the selection of photocatalysts for CO₂ reduction should be based on the reaction system (gas-phase or liquid-phase) and specific requirements, while advanced equipment such as the Labsolar-6A system plays a key role in improving experimental efficiency and reliability, providing technical support for sustainable development.
Recommended
news
