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A glut of dinitrogen‐derived ammonia (NH3) over the past century has resulted in a heavily imbalanced nitrogen cycle and consequently, the large‐scale accumulation of reactive nitrogen such as nitrates in our ecosystems has led to detrimental environmental issues. Electrocatalytic upcycling of waste nitrogen back into NH3 holds promise in mitigating these environmental impacts and reducing reliance on the energy‐intensive Haber–Bosch process. Herein, we report a high‐performance electrolyzer using an ultrahigh alkalinity electrolyte, NaOH−KOH−H2O, for low‐cost NH3 electrosynthesis. At 3,000 mA/cm2, the device with a Fe−Cu−Ni ternary catalyst achieves an unprecedented faradaic efficiency (FE) of 92.5±1.5 % under a low cell voltage of 3.83 V; whereas at 1,000 mA/cm2, an FE of 96.5±4.8 % under a cell voltage of only 2.40 V was achieved. Techno‐economic analysis revealed that our device cuts the levelized cost of ammonia electrosynthesis by ~40 % ($30.68 for Fe−Cu−Ni vs. $48.53 for Ni foam per kmol‐NH3). The NaOH−KOH−H2O electrolyte together with the Fe−Cu−Ni ternary catalyst can enable the high‐throughput nitrate‐to‐ammonia applications for affordable and scalable real‐world wastewater treatments. [ABSTRACT FROM AUTHOR]

At present, the research on highly active and stable nitrogen reduction reaction catalysts is still challenging work for the electrosynthesis of ammonia (NH3). Herein, we synthesized atomically dispersed zinc active sites supported on N‐doped carbon nanosheets (Zn/NC NSs) as an efficient nitrogen reduction reaction catalyst, which achieves a high ammonia yield of 46.62 μg h−1 mg−1cat. at −0.85 V (vs RHE) and Faradaic efficiency of 95.8% at −0.70 V (vs RHE). In addition, Zn/NC NSs present great stability and selectivity, and there is no significant change in NH3 rate and Faradaic efficiencies after multiple cycles. The structural characterization shows that the active center in the nitrogen reduction reaction process is the Zn–N4 sites in the catalyst. DFT calculation confirms that Zn/NC with Zn–N4 configuration has a lower energy barrier for the formation of *NNH intermediate compared with pure N‐doped carbon nanosheets (N‐C NSs), thus promoting the hydrogenation kinetics in the whole nitrogen reduction reaction process. [ABSTRACT FROM AUTHOR]

Cu‐based catalysts have been identified as the most promising candidates for generation of C2+ products in electrochemical CO2 reduction reaction. Defect engineering in catalysts is a widely employed strategy for promoting C−C coupling on Cu. However, comprehensive understanding of defect structure‐to‐activity relationship has not been obtained. In this study, controllable defects generation is achieved, which leads to a series of Cu‐based catalysts with various phase mixing degrees. It is observed that the Faradaic efficiency toward C2+ products increases with the phase mixing degree, reaching 81 % at maximum. In situ infrared absorption spectroscopy reveals that the catalysts with higher phase mixing degree tend to form *CO more easily and possess higher retention of *CO under high overpotential window, thereby promoting C−C coupling. This work sheds new light on the relationship between defects and C−C coupling, and the rational developed of more advanced Cu‐base catalysts. [ABSTRACT FROM AUTHOR]

Surface ligands play an important role in shape‐controlled growth and stabilization of colloidal nanocrystals. Their quick removal tends to cause structural deformation and/or aggregation to the nanocrystals. Herein, we demonstrate that the surface ligand based on poly(vinylpyrrolidone) (PVP) can be slowly removed from Pd nanosheets (NSs, 0.93±0.17 nm in thickness) by simply aging the colloidal suspension. The aged Pd NSs show well‐preserved morphology, together with significantly enhanced stability toward both e‐beam irradiation and electrocatalysis (e.g. ethanol oxidation). It is revealed that the slow desorption of PVP during aging forces the re‐exposed Pd atoms to reorganize, facilitating the surface to transform from being nearly perfect to defect‐rich. The resultant Pd NSs with abundant defects no longer rely on surface ligand to stabilize the atomic arrangement and thus show excellent structural and electrochemical stability. This work provides a facile and effective method to maintain the integrity of colloidal nanocrystals by slowly removing the surface ligand. [ABSTRACT FROM AUTHOR]

Electrochemical carbon dioxide reduction reaction (CO2RR) to produce valuable chemicals is a promising pathway to alleviate the energy crisis and global warming issues. However, simultaneously achieving high Faradaic efficiency (FE) and current densities of CO2RR in a wide potential range remains as a huge challenge for practical implements. Herein, we demonstrate that incorporating bismuth‐based (BH) catalysts with L‐histidine, a common amino acid molecule of proteins, is an effective strategy to overcome the inherent trade‐off between the activity and selectivity. Benefiting from the significantly enhanced CO2 adsorption capability and promoted electron‐rich nature by L‐histidine integrity, the BH catalyst exhibits excellent FEformate in the unprecedented wide potential windows (>90 % within −0.1–−1.8 V and >95 % within −0.2–−1.6 V versus reversible hydrogen electrode, RHE). Excellent CO2RR performance can still be achieved under the low‐concentration CO2 feeding (e.g. 20 vol.%). Besides, an extremely low onset potential of −0.05 VRHE (close to the theoretical thermodynamic potential of −0.02 VRHE) was detected by in situ ultraviolet‐visible (UV‐Vis) measurements, together with stable operation over 50 h with preserved FEformate of ≈95 % and high partial current density of 326.2 mA cm−2 at −1.0 VRHE. [ABSTRACT FROM AUTHOR]