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Highlights: Oxygen-coordinated single-atom Mn catalyst was fabricated via introducing oxygen functional groups rich bacterial cellulose as the adsorption regulator through a combined impregnation–pyrolysis–etching synthetic route. Mn–O–C as the electrocatalyst exhibits superior electrocatalytic activity toward ammonia synthesis with a maximum NH3 yield rate of 1476.9 ± 62.6 μg h−1 cm−2 at − 0.7 V (vs. RHE) and a faradaic efficiency of 89.0 ± 3.8% at − 0.5 V (vs. RHE) under ambient conditions. Electrocatalytic mechanism of Mn–(O–C2)4 site for nitrate reduction reaction is unveiled by a combination of in situ spectroscopy characterization and computational study. Electrocatalytic nitrate reduction reaction has attracted increasing attention due to its goal of low carbon emission and environmental protection. Here, we report an efficient NitRR catalyst composed of single Mn sites with atomically dispersed oxygen (O) coordination on bacterial cellulose-converted graphitic carbon (Mn–O–C). Evidence of the atomically dispersed Mn–(O–C2)4 moieties embedding in the exposed basal plane of carbon surface is confirmed by X-ray absorption spectroscopy. As a result, the as-synthesized Mn–O–C catalyst exhibits superior NitRR activity with an NH3 yield rate (RNH3) of 1476.9 ± 62.6 μg h−1 cm−2 at − 0.7 V (vs. reversible hydrogen electrode, RHE) and a faradaic efficiency (FE) of 89.0 ± 3.8% at − 0.5 V (vs. RHE) under ambient conditions. Further, when evaluated with a practical flow cell, Mn–O–C shows a high RNH3 of 3706.7 ± 552.0 μg h−1 cm−2 at a current density of 100 mA cm−2, 2.5 times of that in the H cell. The in situ FT-IR and Raman spectroscopic studies combined with theoretical calculations indicate that the Mn–(O–C2)4 sites not only effectively inhibit the competitive hydrogen evolution reaction, but also greatly promote the adsorption and activation of nitrate (NO3−), thus boosting both the FE and selectivity of NH3 over Mn–(O–C2)4 sites. [ABSTRACT FROM AUTHOR]

Accelerating slow water dissociation kinetics is key to boosting the hydrogen evolution reaction (HER) in alkaline media. We report the synthesis of atomically dispersed MoOx species anchored on Rh metallene using a one‐pot solvothermal method. The resulting structures expose the oxide‐metal interfaces to the maximum extent. This leads to a MoOx‐Rh catalyst with ultrahigh alkaline HER activity. We obtained a mass activity of 2.32 A mgRh−1 at an overpotential of 50 mV, which is 11.8 times higher than that of commercial Pt/C and surpasses the previously reported Rh‐based electrocatalysts. First‐principles calculations demonstrate that the interface between MoOx and Rh is the active center for alkaline HER. The MoOx sites preferentially adsorb and dissociate water molecules, and adjacent Rh sites adsorb the generated atomic hydrogen for efficient H2 evolution. Our findings illustrate the potential of atomic interface engineering strategies in electrocatalysis. [ABSTRACT FROM AUTHOR]

Non‐precious‐metal (NPM) catalysts often face the formidable challenge of a trade‐off between long‐term stability and high activity, which has not yet been widely addressed. Herein we propose a distinct molecule‐selective fence as a promising concept to solve this activity‐stability trade‐off. The fence encloses the catalyst and prevents species poisonous to the catalyst from reaching it, but allows catalytic reaction‐related species to diffuse freely. We constructed a CoS2 fence layer on the external surface of highly active cobalt‐doped MoS2, achieving a remarkable catalytic stability towards the alkaline hydrogen evolution reaction and improved activity. In situ spectroscopy uncovered the underlying molecular mechanism of the CoS2 fence for breaking the activity‐stability trade‐off of the MoS2 catalyst. This work offers valuable guidance for rationally designing efficient and stable NPM catalysts. [ABSTRACT FROM AUTHOR]

Herein, we report a comprehensive strategy to synthesize a full range of single‐atom metals on carbon matrix, including V, Mn, Fe, Co, Ni, Cu, Ge, Mo, Ru, Rh, Pd, Ag, In, Sn, W, Ir, Pt, Pb, and Bi. The extensive applications of various SACs are manifested via their ability to electro‐catalyze typical hydrogen evolution reactions (HER) and conversion reactions in novel room‐temperature sodium sulfur batteries (RT‐Na‐S). The enhanced performances for these electrochemical reactions arisen from the ability of different single active atoms on local structures to tune their electronic configuration. Significantly, the electrocatalytic behaviors of diverse SACs, assisted by density functional theory calculations, are systematically revealed by in situ synchrotron X‐ray diffraction and in situ transmission electronic microscopy, providing a strategic library for the general synthesis and extensive applications of SACs in energy conversion and storage. [ABSTRACT FROM AUTHOR]

For electrocatalysts for the hydrogen evolution reaction (HER), encapsulating transition metal phosphides (TMPs) into nitrogen‐doped carbon materials has been known as an effective strategy to elevate the activity and stability. Yet still, it remains unclear how the TMPs work synergistically with the N‐doped support, and which N configuration (pyridinic N, pyrrolic N, or graphitic N) contributes predominantly to the synergy. Here we present a HER electrocatalyst (denoted as MoP@NCHSs) comprising MoP nanoparticles encapsulated in N‐doped carbon hollow spheres, which displays excellent activity and stability for HER in alkaline media. Results of experimental investigations and theoretical calculations indicate that the synergy between MoP and the pyridinic N can most effectively promote the HER in alkaline media. [ABSTRACT FROM AUTHOR]

The highly efficient electrochemical hydrogen evolution reaction (HER) provides a promising pathway to resolve energy and environment problems. An electrocatalyst was designed with single Mo atoms (Mo-SAs) supported on N-doped carbon having outstanding HER performance. The structure of the catalyst was probed by aberration-corrected scanning transmission electron microscopy (AC-STEM) and X-ray absorption fine structure (XAFS) spectroscopy, indicating the formation of Mo-SAs anchored with one nitrogen atom and two carbon atoms (Mo1N1C2). Importantly, the Mo1N1C2 catalyst displayed much more excellent activity compared with Mo2C and MoN, and better stability than commercial Pt/C. Density functional theory (DFT) calculation revealed that the unique structure of Mo1N1C2 moiety played a crucial effect to improve the HER performance. This work opens up new opportunities for the preparation and application of highly active and stable Mo-based HER catalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ru clusters are immobilized on hierachical Ni 3 N arrays. • The interfacial Ru atoms enable long-range Ni atoms as active sites via electron delocalization. • The H 2 O and H* adsorption energies are strengthened and weakened, respectively. • An outperforming Pt/C benchmark activity is achieved at ≥ 125 mA cm−2. Hydrogen (H 2) production from alkaline water electrocatalysis is economically appealing yet significantly hindered by the sluggish H 2 O adsorption and H* binding kinetics on active sites during hydrogen evolution reaction (HER). Herein, we interfacially immobilize Ru clusters on the hierarchical nickel nitride (Ru-Ni 3 N) nanosheet arrays via the filling of Ru3+ species into the metal vacancies of nickel hydroxide precursors and the subsequent controllable nitridation. The optimized Ru-Ni 3 N shows the outstanding HER performance, affording a 30-fold rise in the intrinsic activity of Ni sites, a outperforming-Pt/C overpotential at ≥ 125 mA cm−2 while remaining a robust stability. We further establish by a combined study of density functional theory (DFT) calculations with experimental analyses that long-range Ni sites around Ru sites act as active sites via the electron delocalization, remarkably weakening the H 2 O adsorption and H* binding barriers for enhancing the alkaline HER kinetics. Moreover, it also demonstrates an excellent pH-universal HER and overall water splitting performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • We report a cheaper yet higher efficient HER electrocatalyst than Pt. • The Ru@2D-NC is synthesized though a simple organic/aqueous interfacial strategy. • It exhibits low η @10 of 31 and 29 mV in alkaline and acidic media respectively. • Optimized ΔG(H*) and ΔG B (H 2 O) are obtained via interatomic charge redistribution. • The strong Ru-support interaction endows the catalyst with excellent durability. The development of efficient and durable electrocatalysts for hydrogen evolution reaction (HER) is crucial for sustainable electrochemical water splitting and its practical application. However, the inappropriate binding with H* and sluggish reaction kinetics limit their overall HER performance, especially in alkaline electrolyte. Herein, we report a robust and high active HER electrocatalyst with optimized metal-H* interaction and low water dissociation energy barrier through interatomic d-p orbital hybridization. The Ru nanoparticles with mean size down to 1.7 nm are anchored on two-dimension nitrogen-doped carbon nanocone arrays via a facile aqueous-organic interfacial method. This unique architecture induces strong interaction between Ru and the carbon support. Electrons are transferred from Ru to the N-doped carbon, causing a shift of charge distribution and modified surface properties of Ru. Furthermore, the newly emerged Ru-N bonds endow the catalyst with high structure robustness. As a result, the catalyst exhibits superior HER performances in both alkaline and acidic electrolytes, with low overpotentials (31 and 29 mV at 10 mA cm−2 respectively), high H 2 turn over frequency (2.20 s−1 at the overpotential of 25 mV) and excellent durability (10,000 cycles). The density functional theory calculations reveal that the boosted HER activity can be attributed to the downshift of the d-band center of Ru, which lowers the |ΔG(H*)| and accelerates the H-OH cleavage. [ABSTRACT FROM AUTHOR]