The limitations of the Haber–Bosch reaction, particularly high-temperature operation, have ignited new interests in low-temperature ammonia-synthesis scenarios. Ambient N2 electroreduction is a compelling alternative but is impeded by a low ammonia production rate (mostly <10 mmol gcat –1 h–1), a small partial current density (<1 mA cm–2), and a high-selectivity hydrogen-evolving side reaction. Herein, we report that room-temperature nitrate electroreduction catalyzed by strained ruthenium nanoclusters generates ammonia at a higher rate (5.56 mol gcat –1 h–1) than the Haber–Bosch process. The primary contributor to such performance is hydrogen radicals, which are generated by suppressing hydrogen–hydrogen dimerization during water splitting enabled by the tensile lattice strains. The radicals expedite nitrate-to-ammonia conversion by hydrogenating intermediates of the rate-limiting steps at lower kinetic barriers. The strained nanostructures can maintain nearly 100% ammonia-evolving selectivity at >120 mA cm–2 current densities for 100 h due to the robust subsurface Ru–O coordination. These findings highlight the potential of nitrate electroreduction in real-world, low-temperature ammonia synthesis.

photocopying process took nearly a century from 1843 until the early 1940s, while the detailed crystal structure of PB was first confirmed as cubic by Ludi and co-workers in 1977, which is now widely accepted. [6] Remarkably, the past four decades have witnessed the exploration of PB in more and more new and totally different, but very promising application areas, reaching from rechargeable batteries [7] to catalysis [8] and biosensors, [9] from optically switchable films in electrochromic devices (smart windows) [10] to a helpful nanomaterial for cancer therapy. [11] Due to their excellent redox activity, low cost, and highly reversible phase transitions during the insertion/extraction process of certain cations, PB and PBAs have also been widely investigated as promising active materials for energy storage devices, especially for commercial sodium-ion batteries (SIBs) beyond other batteries system (potassium-ion batteries, [12,13] lithium-ion batteries (LIBs), [14] lithium-sulfur batteries (LI-S), [15] lithium-air batteries, [16] zinc-air batteries, [17] solid-state batteries, [18] etc.) in large-scale stationary energy storage systems in the near future. [19,20] The chemical formulas of PBAs could be represented asHere, A represents a single alkali metal or alkaline earth metal, or a mixture of these metals, while M 1 and M 2 typically are transition metals bonded by CN − bonds to form a 3D open structure with the capability to host element(s) A inside the crystal structure. □ represents the vacancy that is caused by the loss of an M 2 (CN) 6 group and the occupation by coordination water and interstitial water, the species and ionic radii of which are shown in Figure 2a. [21] With the different species and various ratios of A/M 1 /M 2 , the number of family members could reach more than 100, sharing different crystal phases, including monoclinic, [22,23] rhombohedral, [24,25] cubic, [26,27] tetragonal, [28] hexagonal, [29] etc. According to the amount of redox-active sites for battery application, PB and PBAs could be divided into dual-electron transfer type (DE-PBAs: M 1 and M 2 = Mn, Fe, Co) and single-electron transfer type (SE-PBAs: M 1 = Zn, Ni and M 2 = Fe, Co, Mn) with theoretical specific capacity of 170 and 85 mAh g −1 , respectively. [21] Taking the high average voltage and capacity of the DE-PBAs into consideration, they are promising and competitive, even to the level of LiFePO 4 (a well-known cathode material for the LIBs), for high energy density devices (≈450 Wh kg −1 on the material level). On the other hand, the negligible structural distortion and high conductivity of SE-PBAs make them desirable choices for fast-charging and long-life devices. [20,30] Prussian blue analogues (PBAs) have attracted wide attention for their application in the energy storage and conversion field due to their low cost, facile synthesis, and appreciable electrochemical performance. At the present stage, most research on PBAs is focused on their material-level optimization, whereas their properties in practical b...

The electrochemical performances of 1D SnO2 nanomaterials, nanotubes, nanowires, and nanopowders, are compared to define the most favorable morphology when SnO2 nanomaterials are adopted as the electrode material for lithium‐ion batteries. Changes in the morphology of SnO2 are closely related with its electrochemical performance. Some SnO2 nanomaterials feature not only an increased energy density but also enhanced Li+ transfer. The correlation between the morphological characteristics and the electrochemical properties of SnO2 nanomaterials is discussed. The interesting electrochemical results obtained here on SnO2 nanomaterials indicate the possibility of designing and fabricating attractive nanostructured materials for lithium‐ion batteries.