The Multifaceted Roles of Carbon Dots in Smart Semiconductor Photocatalytic Systems for Solar-Driven Chemistry

Efficient conversion of solar energy into chemicals is regarded as one of the most promising technologies to alleviate the energy crisis and environmental issues. Smart semiconductor photocatalytic systems (SSPS) have garnered significant attention due to their potential in sustainable energy production, green chemical industry, and environmental remediation. Herein, the ‘smart’ nature of SSPS refers to their abilities to adjust reaction pathways, synergize various effects, and integrate multiple functions, thereby enhancing catalytic performance and surpassing the ordinary composite semiconductor photocatalytic systems (CSPS). Among the various nanomaterials explored to date, Carbon dots (CDs) have emerged as a promising “element” to design SSPS due to their unique physical and chemical properties, e.g., abundant functional groups, structural designability, superior optical properties, low toxicity, high stability, and outstanding electron-transfer ability. In this review, we summarize the latest advancements that utilize CDs to design highly efficient SSPS to address interdisciplinary challenges especially in water splitting, organic synthesis, CO2 reduction reaction (CO2RR), and pollutant degradation. We especially highlight the roles of CDs in adjusting reaction pathways, synergizing various effects, and integrating multiple functions with up-to-date examples and applications. In the last part, we discuss the challenges people are facing and look ahead to the future expectations, along with viable suggestions for the future development of CDs-based SSPS.