Carbon neutrality is one of the central topics of not only the scientific community but also the majority of human society. The development of highly efficient carbon dioxide (CO2) capture and utilization (CCU) techniques is expected to stimulate routes and concepts to go beyond fossil fuels and provide more economic benefits for a carbon-neutral economy. While various single-carbon (C1) and multi-carbon (C2+) products have been selectively produced to date, the scope of CCU can be further expanded to more valuable chemicals beyond simple carbon species by integration of nitrogenous reactants into CO2 reduction. In this Review, research progress toward sustainable production of high-value-added chemicals (urea, methyl­amine, ethyl­amine, formamide, acetamide, and glycine) from catalytic coupling of CO2 and nitrogenous small molecules (NH3, N2, NO3 –, and NO2 –) is highlighted. C–N bond formation is a key mechanistic step in N-integrated CO2 reduction, so we focus on the possible pathways of C–N coupling starting from the CO2 reduction and nitrogenous small molecules reduction processes as well as the catalytic attributes that enable the C–N coupling. We also propose research directions and prospects in the field, aiming to inspire future investigations and achieve comprehensive improvement of the performance and product scope of C–N coupling systems.

Electrochemical reduction of CO 2 (CO 2 RR) and nitrogen (NRR) constitute alternatives to fossil fuel-based technologies for the production of high-valueadded chemicals. Yet their practical application is still hampered by the low energy and Faradaic efficiencies although numerous efforts have been paid to overcome the fatal shortcomings. To date, most studies have focused on designing and developing advanced electrocatalysts, while the understanding of electrolyte, which would significantly influence the reaction microenvironment, are still not enough to provide insight to construct highly active and selective electrochemical systems. Here, a comprehensive review of the different electrolytes participating in the CO 2 RR and NRR is provided, including acidic, neutral, alkaline, and water-in-salt electrolyte as aqueous electrolytes, as well as organic electrolyte, ionic-liquids electrolyte, and the mixture of the two as non-aqueous electrolytes. Through the discussion of the roles of these various electrolytes, it is aimed to grasp their essential function during the electrochemical process and how these functions can be used as design parameters for improving electrocatalytic performance. Finally, priorities for future studies are suggested to support the in-depth understanding of the electrolyte effects and thus guide efficient selection for next-generation gasinvolving electrochemical reactions.

Photocatalytic nitrogen reduction reaction (PNRR) is emerging as a sustainable ammonia synthesis approach to meet global carbon neutrality. Porous framework materials with well‐designed structures have great opportunities in PNRR; however, they suffer from unsatisfactory activity in the conventional gas‐in‐solvent system (GIS), owing to the hindrance of nitrogen utilization and strong competing hydrogen evolution caused by overwhelming solvent. In this study, porous framework materials are combined with a novel “solvent‐in‐gas” system, which can bring their superiority into full play. This system enables photocatalysts to directly operate in a gas‐dominated environment with a limited proton source uniformly suspended in it, achieving the accumulation of high‐concentrated nitrogen within porous framework while efficiently restricting the solvent‐photocatalyst contact. An over eightfold increase in ammonia production rate (1820.7 µmol g−1 h−1) compared with the conventional GIS and an apparent quantum efficiency as high as ≈0.5% at 400 nm are achieved. This system‐level strategy further finds applicability in photocatalytic CO2 reduction, featuring it as a staple for photosynthetic methodology.

Substantial progress has been made in the understanding of gas‐involving electrochemical reactions recently for the sake of clean, renewable, and efficient energy technologies. However, the specific influence mechanism of the microenvironment at the reaction interface on the electrocatalytic performance (activity, selectivity, and durability) remains unclear. Here, we provide a comprehensive understanding of the interfacial microenvironment of gas‐involving electrocatalysis, including carbon dioxide reduction reaction and nitrogen reduction reaction, and classify the factors affecting the reaction thermodynamics and kinetics into gas diffusion, proton supply, and electron transfer. This categorization allows a systematic survey of the literature focusing on electrolyzer‐level (optimization of the device, control of the experimental condition, and design of the working electrode), electrolyte‐level (increase of gas solubility, regulation of proton supply, and substitution of anodic reaction), and electrocatalyst‐level strategies (promotion of gas affinity, adjustment of hydrophobicity, and enhancement of conductivity), aiming to retrieve the correlations between the microenvironment and electrochemical performance. Finally, priorities for future studies are suggested to support the comprehensive improvement of next‐generation gas‐involving electrochemical reactions.