Novel carbon-based catalyst developed for efficient photo-driven CO2 cycloaddition

Prof. Chen Liang's group and Prof. Lu Zhiyi's group at the Ningbo Institute of Materials Technology and Engineering (NIMTE) of the Chinese Academy of Sciences (CAS) proposed a highly-active carbon-based catalyst, which can directly utilize renewable energy (e.g., solar energy) to improve the efficiency of photo-driven CO₂ cycloaddition effectively. The study was published in Advanced Materials.

In recent years, the increasing greenhouse gas (mainly CO₂) emissions have exacerbated the global warming and ocean acidification. With the aim to peak CO₂ emissions and achieve carbon neutrality, the elimination of CO₂ based on the capture and conversion of CO₂ is urgently needed. The cycloaddition of CO₂ with epoxides to generate cyclic carbonates has attracted extensive attention thanks to the diverse application of products.

By virtue of a versatile molecule-confined pyrolysis strategy, researchers at NIMTE proposed and synthesized a semiconductive Al-N-C catalyst possessing high density of atomically dispersed Al-N₄ motifs.

The Al and N species serves as Lewis acid and base sites, respectively, which are combined to facilitate the substrate activation for the photo-driven CO₂ cycloaddition reactions. Under light irradiation, the synthesized Al–N–C catalyst showed excellent catalytic performance (≈95% conversion, reaction rate = 3.52 mmol g^-1 h^-1) for the CO₂ cycloaddition reaction.

In addition, both experimental and theoretical analysis revealed that light irradiation facilitated the photo-generated electron transfer from the semiconductive Al–N–C catalyst to the epoxide reactant, contributing to the high-efficiency formation of a ring-opened intermediate through the rate-limiting step. This process constitutes a new activation mechanism for CO₂ cycloaddition reaction.

This study has provided a novel approach for high-efficiency CO₂ cycloaddition based on the integration of atomically dispersed Al species and photothermal effect, and shed light on the future design of advanced catalysts for diverse catalytic reactions.