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The electrochemical C‐N coupling process, facilitating the production of organic nitrogen substances (such as urea, methylamine, formamide, and ethylamine) via the simultaneous reduction of carbon dioxide (CO2) and small nitrogen‐based substances, stands at the forefront of advancing carbon neutrality and the artificial nitrogen cycle. This method has garnered substantial interest due to its potential economic and environmental benefits. Although considerable progress has been achieved in this emerging field, it still faces challenges, including slow reactant adsorption, competing side reactions, and complex multi‐step pathways, resulting in low yields and selectivity. Strategically designing and developing low‐cost and exceptionally performant catalysts is crucial for cost‐effective and precise electrochemical C─N bonding. This article offers an in‐depth review of the electrosynthesis of valuable organic nitrogen compounds at ambient conditions from earth‐abundant resources/wastes, such as CO2 and small nitrogenous molecules (nitrogen: N2, nitrite: NO2−, nitrate: NO3−, ammonia: NH3, etc.), via electrochemical C─N bond formation reactions, especially using carbon‐based catalysts. The relevant electrochemical C─N bond formation mechanisms, the design principles of advanced carbon‐based electrocatalysts, and the impact of different electrolyser designs are discussed, along with the present obstacles and upcoming prospects in this dynamic field. [ABSTRACT FROM AUTHOR]

Oxide-derived Cu catalysts from Cu2O microcrystals are capable of electro-chemically converting CO2 into various value-added chemicals. However, their structural transformation and associated preferred products remain unclear, requiring further investigation. Herein, Cu2O microcrystals with controllable low- and high-index facets exposure are fabricated to differentiate the effects of initial exposed facets on their structural reconstruction and product selectivity in electrochemical CO2 reduction reaction. Combined in situ characterizations and theoretical investigation reveal the direct correlations of Cu2O reconstruction and product selectivity to its initial facet exposure. The Cu2O low-index facet, being more stable with a high energy barrier on material reduction, tends to partially maintain its original crystalline structure and larger Cu2O particle size throughout the transformation. The derived flatter surface and limited Cu2O/ Cu interfaces result in a favorable selectivity toward 2-electron transfer products. The chemically active Cu2O high-index facet (311) is energetically favorable to be reduced owing to the feasible protonation process, thus experiencing a drastic reconstruction with rich newly formed Cu nanoparticles and evolved fine Cu2O grains; Such a reconstruction creates uncoordinated Cu species and abundant boundaries, benefiting charge transfer and increasing the local pH by confining OH-, thus leading to a high selectivity toward C2+ products. [ABSTRACT FROM AUTHOR]

The electrochemical oxygen reduction reaction (ORR) provides a green route for decentralized H2O2 synthesis, where a structure–selectivity relationship is pivotal for the control of a highly selective and active two‐electron pathway. Here, we report the fabrication of a boron and nitrogen co‐doped turbostratic carbon catalyst with tunable B−N−C configurations (CNB‐ZIL) by the assistance of a zwitterionic liquid (ZIL) for electrochemical hydrogen peroxide production. Combined spectroscopic analysis reveals a fine tailored B−N moiety in CNB‐ZIL, where interfacial B−N species in a homogeneous distribution tend to segregate into hexagonal boron nitride domains at higher pyrolysis temperatures. Based on the experimental observations, a correlation between the interfacial B−N moieties and HO2− selectivity is established. The CNB‐ZIL electrocatalysts with optimal interfacial B−N moieties exhibit a high HO2− selectivity with small overpotentials in alkaline media, giving a HO2− yield of ≈1787 mmol gcatalyst−1 h−1 at −1.4 V in a flow‐cell reactor. [ABSTRACT FROM AUTHOR]

Closing both the carbon and nitrogen loops is a critical venture to support the establishment of the circular, net‐zero carbon economy. Although single atom catalysts (SACs) have gained interest for the electrochemical reduction reactions of both carbon dioxide (CO2RR) and nitrate (NO3RR), the structure–activity relationship for Cu SAC coordination for these reactions remains unclear and should be explored such that a fundamental understanding is developed. To this end, the role of the Cu coordination structure is investigated in dictating the activity and selectivity for the CO2RR and NO3RR. In agreement with the density functional theory calculations, it is revealed that Cu‐N4 sites exhibit higher intrinsic activity toward the CO2RR, whilst both Cu‐N4 and Cu‐N4−x‐Cx sites are active toward the NO3RR. Leveraging these findings, CO2RR and NO3RR are coupled for the formation of urea on Cu SACs, revealing the importance of *COOH binding as a critical parameter determining the catalytic activity for urea production. To the best of the authors' knowledge, this is the first report employing SACs for electrochemical urea synthesis from CO2RR and NO3RR, which achieves a Faradaic efficiency of 28% for urea production with a current density of −27 mA cm–2 at −0.9 V versus the reversible hydrogen electrode. [ABSTRACT FROM AUTHOR]

Electrochemical oxygen reduction provides an eco-friendly synthetic route to hydrogen peroxide (H2O2), a widely used green chemical. However, the kinetically sluggish and low-selectivity oxygen reduction reaction (ORR) is a key challenge to electrochemical production of H2O2 for practical applications. Herein, we demonstrate that single cobalt atoms anchored on oxygen functionalized graphene oxide form Co-O-C@GO active centres (abbreviated as Co1@GO for simplicity) that act as an efficient and durable electrocatalyst for H2O2 production. This Co1@GO electrocatalyst shows excellent electrochemical performance in O2-saturated 0.1 M KOH, exhibiting high reactivity with an onset potential of 0.91 V and H2O2 production of 1.0 mg cm−2 h−1 while affording high selectivity of 81.4% for H2O2. Our combined experimental observations and theoretical calculations indicate that the high reactivity and selectivity of Co1@GO for H2O2 electrogeneration arises from a synergistic effect between the O-bonded single Co atoms and adjacent oxygen functional groups (C-O bonds) of the GO present in the Co-O-C active centres. Hydrogen peroxide is an industrially highly demanded chemical, but its electrochemical synthesis still suffers from sluggish kinetics and imperfect selectivity. Here, the authors report a catalyst material comprising single cobalt atoms anchored on oxygen functionalized graphene oxide that produces 1.0 mg cm−2 h−1 of H2O2 with high selectivity and a low onset potential. [ABSTRACT FROM AUTHOR]

Rational design of cost‐effective and active electrocatalysts is an essential step toward the large‐scale realization of hydrogen fuel cells and metal–air batteries. Its success requires a drastic improvement in the kinetics of the cathodic oxygen reduction reaction (ORR). Herein, a novel ORR catalyst formed by encapsulating thin Cu layer decorated Co nanoparticles inside graphitic carbon layers that are embedded with abundant CoNx and CuNx atomic sites (denoted as SA‐CoCu@Cu/CoNP), is reported. The multicomponent SA‐CoCu@Cu/CoNP composite exhibits a remarkable ORR catalytic activity, exceptional stability, and excellent methanol tolerance in alkaline media, outperforming the commercial platinum carbon under identical testing conditions and also being active in acidic media. The excellent ORR catalytic performance is ascribed to the modified electronic structure of the CoNx active sites due to an electron donating effect from the embedded nanoparticles and the nearby CuNx species, as revealed by X‐ray spectroscopic results and density functional theory computations. Moreover, the effective role of CuNx sites in suppressing the peroxide formation during ORR is also identified, endowing the resultant catalyst a prolonged stability and enhanced efficiency that are beneficial for practical applications. [ABSTRACT FROM AUTHOR]

In this study, scalable, flame spray synthesis is utilized to develop defective ZnO nanomaterials for the concurrent generation of H2 and CO during electrochemical CO2 reduction reactions (CO2RR). The designed ZnO achieves an H2/CO ratio of ≈1 with a large current density (j) of 40 mA cm−2 during long‐term continuous reaction at a cell voltage of 2.6 V. Through in situ atomic pair distribution function analysis, the remarkable stability of these ZnO structures is explored, addressing the knowledge gap in understanding the dynamics of oxide catalysts during CO2RR. Through optimization of synthesis conditions, ZnO facets are modulated which are shown to affect reaction selectivity, in agreement with theoretical calculations. These findings and insights on synthetic manipulation of active sites in defective metal‐oxides can be used as guidelines to develop active catalysts for syngas production for renewable power‐to‐X to generate a range of fuels and chemicals. [ABSTRACT FROM AUTHOR]

Defective 3D vertical graphene (VG) with a relatively large surface area, high defect density, and increased surface electrons is synthesized via a scalable plasma enhanced chemical vapor deposition method, together with a postsynthesis Ar‐plasma treatment (VG‐Ar). Subsequently, Cu@CuxO nanoparticles are deposited onto VG‐Ar (Cu/VG‐Ar) through a galvanostatic pulsed electrodeposition method. These Cu@CuxO nanocatalyst systems exhibit a superior electrochemical CO2 reduction performance when compared to Cu‐based catalysts supported on commercial graphene paper or pristine VG without postsynthesis Ar‐plasma treatment. The Cu/VG‐Ar achieves the highest CO2 reduction Faradaic efficiency of 60.6% (83.5% of which are attributed to liquid products, i.e., formate, ethanol, and n‐propanol) with a 5.6 mA cm−2 partial current density at −1.2 V versus reversible hydrogen electrode (RHE). The improved CO2 reduction performance of Cu/VG‐Ar originates from the well‐dispersed Cu@CuxO nanoparticles deposited on the defective VG‐Ar. The intrinsic carbon defects on VG‐Ar can suppress the hydrogen evolution reaction as well as tune the interaction between VG and Cu@CuxO, thus impeding the excessive oxidation of Cu2O species deposited on VG‐Ar. The defective VG‐Ar and stabilized Cu@CuxO enhances CO2 adsorption and promotes electron transfer to the adsorbed CO2 and intermediates on the catalyst surface, thus improving the overall CO2 reduction performance. [ABSTRACT FROM AUTHOR]

Renewable‐electricity‐powered electrocatalytic CO2 reduction reactions (CO2RR) have been identified as an emerging technology to address the issue of rising CO2 emissions in the atmosphere. While the CO2RR has been demonstrated to be technically feasible, further improvements in catalyst performance through active sites engineering are a prerequisite to accelerate its commercial feasibility for utilization in large CO2‐emitting industrial sources. Over the years, the improved understanding of the interaction of CO2 with the active sites has allowed superior catalyst design and subsequent attainment of prominent CO2RR activity in literature. This review tracks the evolution of the understanding of CO2RR active sites on different electrocatalysts such as metals, metal‐oxides, single atoms, metal‐carbon, and subsequently metal‐free carbon‐based catalysts. Despite the tremendous research efforts in the field, many scientific questions on the role of various active sites in governing CO2RR activity, selectivity, stability, and pathways are still unanswered. These gaps in knowledge are highlighted and a discussion is set forth on the merits of utilizing advanced in‐situ and operando characterization techniques and machine learning (ML). Using this technique, the underlying mechanisms can be discerned, and as a result new strategies for designing active sites may be uncovered. Finally, this review advocates an interdisciplinary approach to discover and design CO2RR active sites (rather than focusing merely on catalyst activity) in a bid to stimulate practical research for industrial application. [ABSTRACT FROM AUTHOR]

Atomic Co Nx sites, atomic Cu Nx sites, electronic modification, oxygen reduction, peroxide mitigation The unique structure of the obtained catalyst triggers synergies between cobalt and copper species, resulting in improved oxygen reduction performance in alkaline media. Oxygen Reduction Reaction: Electronically Modified Atomic Sites Within a Multicomponent Co/Cu Composite for Efficient Oxygen Electroreduction (Adv. [Extracted from the article]

Hydrogen peroxide produced by electrochemical oxygen reduction reaction provides a potentially cost effective and energy efficient alternative to the industrial anthraquinone process. In this study, we demonstrate that by modulating the oxygen functional groups near the atomically dispersed cobalt sites with proper electrochemical/chemical treatments, a highly active and selective oxygen reduction process for hydrogen peroxide production can be obtained in acidic electrolyte, showing a negligible amount of onset overpotential and nearly 100% selectivity within a wide range of applied potentials. Combined spectroscopic results reveal that the exceptionally enhanced performance of hydrogen peroxide generation originates from the presence of epoxy groups near the Co–N4 centers, which has resulted in the modification of the electronic structure of the cobalt atoms. Computational modeling demonstrates these electronically modified cobalt atoms will enhance the hydrogen peroxide productivity during oxygen reduction reaction in acid, providing insights into the design of electroactive materials for effective peroxide production. The production of hydrogen peroxide by electrochemical oxygen reduction is an attractive alternative to the industrial process, but catalysts should be optimized. Here, the authors enhance hydrogen peroxide production in acidic media with epoxy groups near cobalt centers on carbon nanotubes. [ABSTRACT FROM AUTHOR]

3D Bi2O3 fractal nanostructures (f‐Bi2O3) are directly self‐assembled on carbon fiber papers (CFP) using a scalable hot‐aerosol synthesis strategy. This approach provides high versatility in modulating the physiochemical properties of the Bi2O3 catalyst by a tailorable control of its crystalline size, loading, electron density as well as providing exposed stacking of the nanomaterials on the porous CFP substrate. As a result, when tested for electrochemical CO2 reduction reactions (CO2RR), these f‐Bi2O3 electrodes demonstrate superior conversion of CO2 to formate (HCOO−) with low onset overpotential and a high mass‐specific formate partial current density of −52.2 mA mg−1, which is ≈3 times higher than that of the drop‐casted control Bi2O3 catalyst (−15.5 mA mg−1), and a high Faradaic efficiency (FEHCOO−) of 87% at an applied potential of −1.2 V versus reversible hydrogen electrode. The findings reveal that the high exposure of roughened β‐phase Bi2O3/Bi edges and the improved electron density of these fractal structures are key contributors in attainment of high CO2RR activity. [ABSTRACT FROM AUTHOR]

The large‐scale application of electrochemical reduction of CO2, as a viable strategy to mitigate the effects of anthropogenic climate change, is hindered by the lack of active and cost‐effective electrocatalysts that can be generated in bulk. To this end, SnO2 nanoparticles that are prepared using the industrially adopted flame spray pyrolysis (FSP) technique as active catalysts are reported for the conversion of CO2 to formate (HCOO−), exhibiting a FEHCOO− of 85% with a current density of −23.7 mA cm−2 at an applied potential of −1.1 V versus reversible hydrogen electrode. Through tuning of the flame synthesis conditions, the amount of oxygen hole center (OHC; SnO●) is synthetically manipulated, which plays a vital role in CO2 activation and thereby governing the high activity displayed by the FSP‐SnO2 catalysts for formate production. The controlled generation of defects through a simple, scalable fabrication technique presents an ideal approach for rationally designing active CO2 reduction reactions catalysts. [ABSTRACT FROM AUTHOR]