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Ammonia as an irreplaceable chemical has been widely demanded to keep the sustainable development of the modern society. However, its industrial production consumes huge energy and releases extraordinary green‐house gases, leading to various environmental issues. To achieve the green production of ammonia is a great challenge that has been extensively pursued recently. In the review, a most promising strategy, electrochemical nitrate reduction reaction (e‐NO3RR) for the purpose is comprehensively investigated to give a full understanding of its development and mechanism and provide guidance for future directions. Particularly, the development of electrocatalysts is focused to realize the high ammonia yield rate and Faraday efficiency for industrial applications. The recent‐developed catalysts, including noble metallic materials, alloys, metal compounds, single‐metal‐atom catalysts, and metal‐free materials, are systematically discussed to review the effects of various factors on the catalytic performance in e‐NO3RR. Accordingly, the strategies, including defects engineering, coordination environment modulating, surface controlling, and hybridization, are carefully discussed to improve the catalytic performance, such as the intrinsic activity and selectivity. Finally, perspectives and challenges are given out. This review shall provide insightful guidance on the development of advanced catalytic systems for the production of green ammonia efficiently in the industry. [ABSTRACT FROM AUTHOR]

Spinel oxides, especially Co 3 O 4 , have been considered as ideal electrocatalysts for electrocatalytic nitrate reduction reaction (e-NO 3 RR). However, their application in e-NO 3 RR is still limited because of relatively low activity and selectivity under high potential. Herein, we present that the incorporation of manganese (Mn) into the Co 3 O 4 lattice can achieve the high activity and selectivity in e-NO 3 RR. The Mn-incorporated Co 3 O 4 nanotubes show a remarkable e-NO 3 RR activity with a high ammonia yield rate of 35 mg h−1 cm−2 and excellent selectivity with a Faraday efficiency for ammonia up to 99.5% in neutral media, which are much better than those of transition-metal oxides. Our calculations further show that the replacement of Co by Mn can tune the adsorption behavior of intermediates, and thus reduces the limiting potential of e-NO 3 RR. We believe that the findings provide an insightful guidance to engineer the spinel oxides for enhanced performance towards ideal products. [Display omitted] • Mn-incorporated Co 3 O 4 nanotubes show the highest ammonia yield rate among transition-metal based oxides. • Mn-incorporated Co 3 O 4 nanotubes show high selectivity and stability of e-NO 3 RR. • the Mn ion only partially replaces Co in the CoO 6 octahedrons of spinel Co 3 O 4. • The synergistically catalytic mechanism for Mn-incorporated Co 3 O 4 was surveyed. [ABSTRACT FROM AUTHOR]

[Display omitted] • The development, advantages, and configurations for applying in-situ/operando Raman techniques. • The applications for elucidating the catalyst evolutions, active sites, electrolyte dependence, etc. • The structure–activity relationship of catalysts from fingerprint information of materials and intermediates. • Multiple in-situ/operando methods and theoretical calculations for interpreting the Raman spectra. • Constructive perspectives to answer the current bottleneck of in-situ/operando Raman measurements. Recently, the electrocatalysis has attracted increasing attention for the sustainable development of society, which has been applied for energy harvesting/storage and pollution control. Therefore, various electrocatalysts have emerged over the past two decades to improve the efficiency and reduce the cost for commercialization. However, a deep understanding of dynamical processes in the electrochemical reactions remains deficient, leading to the waste of effort in the design of electrocatalysts. As the reaction occurs on the surface of electrocatalyst, surface-sensitive technologies are essential to give an in-situ characterization for the dynamical process and guidance on the design of novel catalysts. Fortunately, in-situ/operando Raman technique can provide molecular-level fingerprint information on the surface of material, intermediates, and solvents under working conditions. This review elaborately summarizes recent advances of in-situ / operando Raman studies in probing different electrocatalytic systems. We systematically discuss the development, advantages, and configurations now available for applying these Raman techniques firstly. Then, the focus moves to their applications in five types of electrocatalytic reactions to gain a comprehensive understanding on the mechanisms. Finally, the challenges and perspectives on the future developments of in-situ/operando Raman techniques for electrocatalysis are presented. [ABSTRACT FROM AUTHOR]