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Mn‐based oxides are broadly prospected cathode materials for aqueous Zn‐ion batteries (AZIBs) due to their rich abundance, low cost, and plentiful valence states. However, the further development of Mn‐based oxides is severely restricted by the dissolution of active materials and poor structural stability. Herein, hollow octahedral Pr6O11‐Mn2O3 (denoted as PrO‐MnO) heterostructures are developed through a facile metal–organic framework‐engaged templating approach, which realizes boosted Zn ion storage performance. Pr6O11 can not only effectively suppress the dissolution of Mn to stabilize Mn2O3 but also induce interfacial charge rearrangement and promote electron/ion transfer, contributing to the improved electrochemical activity and stability of PrO‐MnO. Moreover, the rationally designed hollow nanostructure offers sufficient active sites and facilitates the reaction kinetics. As expected, the PrO‐MnO cathode exhibits excellent rate and cycling performance with a high reversible capacity of 140.8 mAh g−1 after 2000 cycles at 1 A g−1, outperforming the Mn2O3 cathode. [ABSTRACT FROM AUTHOR]

Aqueous zinc (Zn) metal batteries have considerable potential as large‐scale energy storage systems. However, cathodic metal ions dissolution and anodic dendrite growth constrain their further development. Here, an ion gradient separator is proposed to stabilize the bi‐electrodes of Zn metal batteries. The results show that the constructed low Zn2+ concentration region in the separator helps the NH4V4O10 (NVO) model cathode to maintain good electrolyte wettability and form a N/ZnS/ZnF2‐rich cathode‐electrolyte interphase (CEI), exhibiting a low vanadium (V) dissolution behavior. Meanwhile, the high Zn2+ concentration region in the separator and the flexible solid electrolyte interphase (SEI) inhibit the dendrite growth and parasitic reactions of the Zn metal anode and further prevent the diffusion of V ions. As a proof‐of‐concept, the NVO||Zn battery with gradient separator can achieve 88.1% capacity retention even after cycling over 800 cycles at 1 A g−1, while the ordinary separator only maintains 14.8%. This work presents an innovative gradient separator strategy for achieving high‐performance Zn metal batteries and sheds light on other rechargeable batteries. [ABSTRACT FROM AUTHOR]

While the ambient N2 reduction to ammonia (NH3) using H2O as hydrogen source (2N2+6H2O=4NH3+3O2) is known as a promising alternative to the Haber–Bosch process, the high bond energy of N≡N bond leads to the extremely low NH3 yield. Herein, we report a highly efficient catalytic system for ammonia synthesis using the low‐temperature dielectric barrier discharge plasma to activate inert N2 molecules into the excited nitrogen species, which can efficiently react with the confined and concentrated H2O molecules in porous metal–organic framework (MOF) reactors with V3+, Cr3+, Mn3+, Fe3+, Co2+, Ni2+ and Cu2+ ions. Specially, the Fe‐based catalyst MIL‐100(Fe) causes a superhigh NH3 yield of 22.4 mmol g−1 h−1. The investigation of catalytic performance and systematic characterizations of MIL‐100(Fe) during the plasma‐driven catalytic reaction unveils that the in situ generated defective Fe−O clusters are the highly active sites and NH3 molecules indeed form inside the MIL‐100(Fe) reactor. The theoretical calculation reveals that the porous MOF catalysts have different adsorption capacity for nitrogen species on different catalytic metal sites, where the optimal MIL‐100(Fe) has the lowest energy barrier for the rate‐limiting *NNH formation step, significantly enhancing efficiency of nitrogen fixation. [ABSTRACT FROM AUTHOR]

While the mild production of syngas (a mixture of H2 and CO) from CO2 and H2O is a promising alternative to the coal‐based chemical engineering technologies, the inert nature of CO2 molecules, unfavorable splitting pathways of H2O and unsatisfactory catalysts lead to the challenge in the difficult integration of high CO2 conversion efficiency with produced syngas with controllable H2/CO ratios in a wide range. Herein, we report an efficient plasma‐driven catalytic system for mild production of pure syngas over porous metal–organic framework (MOF) catalysts with rich confined H2O molecules, where their syngas production capacity is regulated by the in situ evolved ligand defects and the plasma‐activated intermediate species of CO2 molecules. Specially, the Cu‐based catalyst system achieves 61.9 % of CO2 conversion and the production of pure syngas with wide H2/CO ratios of 0.05 : 1–4.3 : 1. As revealed by the experimental and theoretical calculation results, the in situ dynamic structure evolution of Cu‐containing MOF catalysts favors the generation of coordinatively unsaturated metal active sites with optimized geometric and electronic characteristics, the adsorption of reactants, and the reduced energy barriers of syngas‐production potential‐determining steps of the hydrogenation of CO2 to *COOH and the protonation of H2O to *H. [ABSTRACT FROM AUTHOR]

Engineering advantageous defects to construct well‐defined active sites in catalysts is promising but challenging to achieve efficient photocatalytic NH3 synthesis from N2 and H2O due to the chemical inertness of N2 molecule. Here, we report defective Fe‐based metal‐organic framework (MOF) photocatalysts via a non‐thermal plasma‐assisted synthesis strategy, where their NH3 production capability is synergistically regulated by two types of defects, namely, bridging organic ligands and terminal inorganic ligands (OH− and H2O). Specially, the optimized MIL‐100(Fe) catalysts, where there are only terminal inorganic ligand defects and coexistence of dual defects, exhibit the respective 1.7‐ and 7.7‐fold activity enhancement comparable to the pristine catalyst under visible light irradiation. As revealed by experimental and theoretical calculation results, the dual defects in the catalyst induce the formation of abundant and highly accessible coordinatively unsaturated Fe active sites and synergistically optimize their geometric and electronic structures, which favors the injection of more d‐orbital electrons in Fe sites into the N2 π* antibonding orbital to achieve N2 activation and the formation of a key intermediate *NNH in the reaction. This work provides a guidance on the rational design and accurate construction of porous catalysts with precise defective structures for high‐performance activation of catalytic molecules. [ABSTRACT FROM AUTHOR]