Electrochemical CO₂ reduction (CO₂RR) offers a promising route to convert CO₂ into value-added fuels and chemicals using renewable electricity. However, most studies rely on high-purity CO₂ feeds, whereas practical carbon sources such as flue gas and air contain dilute CO₂ together with diverse impurities. These conditions lead to sluggish CO₂ mass transport, enhanced hydrogen evolution reaction (HER), and impurity-induced catalyst deactivation, thereby limiting CO₂RR activity, selectivity, and durability. This review systematically summarizes recent advances in low-concentration CO₂ electrochemical capture and conversion, focusing on two main technical routes. The first is capture–conversion coupling, in which CO₂ is captured and subsequently converted in situ into value-added products within single- or dual-cell systems, thereby avoiding energy-intensive capture-medium regeneration, CO₂ compression, and transportation. The second is direct electrolysis of dilute CO₂ streams, which bypasses separate capture units through catalyst design. In both routes, catalyst design has evolved from solely optimizing intrinsic CO₂RR activity toward multifunctional regulation, including captured-CO₂ activation, local CO₂ enrichment, and impurity tolerance. Beyond catalyst development, electrolyzer design, such as gas diffusion layer design, flow-field configuration, and operating condition optimization, is also discussed as a key factor for improving mass transport and stability. Finally, remaining challenges and future opportunities are outlined for selective, durable, and scalable low-concentration CO₂ electrolysis.

Non-thermal plasma (NTP) is an emerging technology for the conversion of CO₂ and CH₄ under mild conditions. This mini review systematically summarizes recent advances in NTP catalysis for the direct conversion of CO₂ and CH₄ into value-added oxygenates, with a focus on two key aspects: catalyst design and reactor optimization. The metal active sites (e.g., Cu, Ni, Co) and their properties (valence state, dispersion) are critical in directing reaction pathways towards specific oxygenates like alcohols or acids, while the support material modulates performance by influencing the local electric field and stabilizing intermediates. Dielectric barrier discharge (DBD) reactors are predominant, and innovations in reactor structure, electrode design (e.g., water electrodes, surface microdischarge), and configuration (e.g., plasma bubble reactors) are crucial for enhancing efficiency and selectivity, even enabling long-chain hydrocarbon formation. Despite progress, challenges in selectivity and energy efficiency remain. Future efforts should focus on rational catalyst design and advanced reactor integration to advance the industrial application of NTP for greenhouse gas valorization.

The electrochemical oxidation of C₂H₄ is attracting increasing attention due to its vast potential market. The current electrochemical methods rely on the use of redox mediators, which may produce corrosive intermediates, while direct oxidation is still limited by its low activity and selectivity. Herein, we conducted electrochemical studies to obtain mechanistic insights into the benchmark Pd catalyst. The generated Pd(Ⅱ) could be the active site for C₂H₄ oxidation. By designing the pulse sequence, we found the ratio of strongly and weakly adsorbed C₂H₄ on Pd to be 0.3:1. The result we obtained provides a guideline for the rational design of high-performance C₂H₄ oxidation catalysts.