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Competition from hydrogen/oxygen evolution reactions and low solubility of N2 in aqueous systems limited the selectivity and activity on nitrogen fixation reaction. Herein, we design an aerobic‐hydrophobic Janus structure by introducing fluorinated modification on porous carbon nanofibers embedded with partially carbonized iron heterojunctions (Fe3C/Fe@PCNF‐F). The simulations prove that the Janus structure can keep the internal Fe3C/Fe@PCNF‐F away from water infiltration and endow a N2 molecular‐concentrating effect, suppressing the competing reactions and overcoming the mass‐transfer limitations to build a robust "quasi‐solid–gas" state micro‐domain around the catalyst surface. In this proof‐of‐concept system, the Fe3C/Fe@PCNF‐F exhibits excellent electrocatalytic performance for nitrogen fixation (NH3 yield rate up to 29.2 μg h−1 mg−1cat. and Faraday efficiency (FE) up to 27.8 % in nitrogen reduction reaction; NO3− yield rate up to 15.7 μg h−1 mg−1cat. and FE up to 3.4 % in nitrogen oxidation reaction). [ABSTRACT FROM AUTHOR]

Highlights: A triple functional additive with a trace amount (1 mM) was proposed to protect Zn anodes. The additive lowers the hydrogen evolution reaction potential, encourages the formation of an in situ solid electrolyte interphase and shields the "tip effect" Dendrite free Zn deposition and highly reversible Zn plating/stripping behaviors were realized by the triple protections Although their cost-effectiveness and intrinsic safety, aqueous zinc-ion batteries suffer from notorious side reactions including hydrogen evolution reaction, Zn corrosion and passivation, and Zn dendrite formation on the anode. Despite numerous strategies to alleviate these side reactions have been demonstrated, they can only provide limited performance improvement from a single aspect. Herein, a triple-functional additive with trace amounts, ammonium hydroxide, was demonstrated to comprehensively protect zinc anodes. The results show that the shift of electrolyte pH from 4.1 to 5.2 lowers the HER potential and encourages the in situ formation of a uniform ZHS-based solid electrolyte interphase on Zn anodes. Moreover, cationic NH4+ can preferentially adsorb on the Zn anode surface to shield the "tip effect" and homogenize the electric field. Benefitting from this comprehensive protection, dendrite-free Zn deposition and highly reversible Zn plating/stripping behaviors were realized. Besides, improved electrochemical performances can also be achieved in Zn//MnO2 full cells by taking the advantages of this triple-functional additive. This work provides a new strategy for stabilizing Zn anodes from a comprehensive perspective. [ABSTRACT FROM AUTHOR]

Molecular complexes with active metal centers exhibit high activity and selectivity for electrochemical CO2 reduction reaction (CO2RR), which represents a promising method for transforming greenhouse gas into valuable chemicals and feedstock. Using metal–organic frameworks (MOFs) to load the active molecular complexes then employing the combination with the carbonic conducting material may exhibit a beneficial effect for CO2RR. Herein, we obtained a composite catalyst named PCN-222(Fe)/CNTs, which was in situ synthesized through the solvothermal method that loads iron porphyrin-centered PCN-222(Fe) molecules onto CNTs. The catalyst PCN-222(Fe)/CNTs exhibits excellent electrocatalytic performance for CO2RR with a FECO of 95.5% (m(Fe-TCPP):m(CNTs) = 1:30, written as PCN-222(Fe)/CNTs-30) and an overpotential (η) of 494 mV. In addition, the turnover frequency (TOF) is high as 448.76 h−1 (3.011 site−1 s−1) and the hydrogen evolution reaction (HER) is indistinctive. After long-term electrocatalysis of 10 h at −0.6 V vs. RHE, PCN-222(Fe)/CNTs-30 remained its high catalytic performance with average FECO = 90%. This work provides a solid foundation for further research in the high-efficiency transformation of CO2 to CO. [ABSTRACT FROM AUTHOR]

Vacancy engineering has been proved repeatedly as an adoptable strategy to boost electrocatalysis, while its poor selectivity restricts the usage in nitrogen reduction reaction (NRR) as overwhelming competition from hydrogen evolution reaction (HER). Revealed by density functional theory calculations, the selenium vacancy in ReSe2 crystal can enhance its electroactivity for both NRR and HER by shifting the d‐band from −4.42 to −4.19 eV. To restrict the HER, we report a novel method by burying selenium vacancy‐rich ReSe2@carbonized bacterial cellulose (Vr‐ReSe2@CBC) nanofibers between two CBC layers, leading to boosted Faradaic efficiency of 42.5 % and ammonia yield of 28.3 μg h−1 cm−2 at a potential of −0.25 V on an abrupt interface. As demonstrated by the nitrogen bubble adhesive force, superhydrophilic measurements, and COMSOL Multiphysics simulations, the hydrophobic and porous CBC layers can keep the internal Vr‐ReSe2@CBC nanofibers away from water coverage, leaving more unoccupied active sites for the N2 reduction (especially for the potential determining step of proton‐electron coupling and transferring processes as *NN → *NNH). [ABSTRACT FROM AUTHOR]

The lack of precise control of particle sizes is the critical challenge in the assembly of 3D interconnected transition‐metal oxide (TMO) for newly‐emerging energy conversion devices. A self‐embedded templating strategy for preparing the TMO@carbon quasiaerogels (TMO@C‐QAs) is proposed. By mimicking an aerogel structure at a microscale, the TMO@C‐QA successfully assembles size‐controllable TMO nanoparticles into 3D interconnected structure with surface‐enriched carbon species. The morphological evolutions of intermediates verify that the self‐embedded Ostwald ripening templating approach is responsible for the dual‐channel TMO@C‐QA formation. The general self‐embedded templating strategy is easily extended to prepare various TMO@C‐QAs, including the Co3O4@C‐QA, Mn3O4@C‐QA, Fe2O3@C‐QA, and NiO@C‐QA. Benefiting from the unparalleled 3D interconnected network of aerogels, the Co3O4@C‐QA displays superior bifunctional catalytic activities for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), as well as high specific capacity and excellent long‐term stability for lithium‐ion battery (LIB) anode. A proof‐of‐concept battery‐powered electrolyzer with Co3O4@C‐QA cathode and anode powered by a full LIB with Co3O4@C‐QA anode is presented. The battery‐powered electrolyzer made of the state‐of‐the‐art TMOs can exhibit great competitive advantages due to its supreme multifunctional energy conversion performance for future water electrolysis. [ABSTRACT FROM AUTHOR]

Electrocatalytic nitrogen reduction reaction (NRR) and hydrogen evolution reaction (HER) are intriguing approaches to nitrogen fixation and hydrogen production under ambient conditions, given the need to discover efficient and stable catalysts to light up the "green chemistry" future. However, bottlenecks are often found during N2/H2O activation, the very first step of NRR/HER, due to energetic electron injection from the surface of electrocatalysts. It is reported that the bottlenecks for both NRR and HER can be tackled by engineering the energy level via low‐valent transition‐metal doping, simultaneously, where rhenium disulfide (ReS2) is employed as a model platform to prove the concept. The doped low‐valent transition‐metal domains (e.g., Fe, Co, Ni, Cu, Zn) in ReS2 provide more active sites for N2/H2O chemisorption and electron transfer, not only weakening the NN/OH bonds for easier dissociation through proton coupling, but also elevating d‐band center toward the Fermi level with more electron energy for N2/H2O reduction. As a result, it is found that iron‐doped ReS2 nanosheets wrapped nitrogen‐doped carbon nanofiber (Fe‐ReS2@N‐CNF) catalyst exhibits superior electrochemical activity with eightfold higher ammonia production yield of 80.4 µg h−1 mg−1cat., and lower onset overpotential of 146 mV and Tafel slope of 63 mV dec−1, when comparing with the pristine ReS2. [ABSTRACT FROM AUTHOR]