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Electrochemical nitrate reduction (NO 3 RR) to ammonia production is regarded as one of the potential alternatives for replacing the Haber-Bosch technology for realizing artificial ammonia synthesis. In this study, a CuCo 2 O 4 /CuO-Ar heterostructure in the shape of dandelion nanospheres formed by nanoarrays has been successfully constructed, demonstrating excellent NO 3 RR performance. Experimental results indicate that Ar plasma etching of CuCo 2 O 4 /CuO-Ar significantly increases the content of oxygen vacancies compared to the sample of CuCo 2 O 4 /CuO-Air etched by air plasma, resulting in improved NO 3 RR performance. Density functional theory calculations further confirm that the existence of more oxygen vacancies effectively decreases the energy barrier of nitrate adsorption, which is due to the generation of more oxygen vacancies facilitating nitrate adsorption and weakening the N-O bonds of nitrate after plasma treatment. As a result, CuCo 2 O 4 /CuO-Ar exhibits a high NH 3 yield of 0.55 mmol h -1 cm -2 and a Faraday efficiency of 95.07% at the optimal potential of -0.9 V (vs RHE) in a neutral medium. Importantly, CuCo 2 O 4 /CuO-Ar also showcases excellent electrocatalytic stability. This study presents new views on the design and structure regulation of NO 3 RR electrocatalysts and their potential applications in the future.

Oxygen evolution reaction (OER) is a limiting reaction for highly efficient water electrolysis. Thus, the development of cost-effective and highly efficient OER catalysts is the key to large-scale water electrolysis for hydrogen production. Herein, by using an interfacial engineering strategy, a unique nanoflower-like Fe 1- x Ni x (PO 3 ) 2 /Ni 2 P/NF heterostructure with abundant heterogeneous interfaces is successfully fabricated. The catalyst exhibits excellent OER catalytic activity in alkaline fresh water and alkaline natural seawater at high current densities, which only, respectively, requires overpotentials of 318 and 367 mV to drive 1000 mA cm -2 in fresh water and natural seawater both containing 1 M KOH. Furthermore, Fe 1- x Ni x (PO 3 ) 2 /Ni 2 P/NF demonstrates excellent durability, which can basically remain stable for 80 h during the electrocatalytic OER processes, respectively, in alkaline fresh water and natural seawater. This work provides a new construction strategy for designing highly efficient electrocatalysts for OER at high current densities both in alkaline fresh water and in natural seawater.

Electrocatalytic nitrate reduction reaction (ENO 3 RR) is an alternative, sustainable, and environmentally friendly value-added NH 3 synthesis method under ambient conditions relative to the traditional Haber-Bosch process; however, its low NH 3 yield, low Faradaic efficiency (FE), low selectivity, and low conversion rate severely restrict the development. In this work, a Cu 2+1 O/Ag-CC heterostructured electrocatalyst was successfully fabricated by constructing a heterogeneous interface between Cu 2+1 O and Ag for selective electrochemical nitrate-to-ammonia conversion. The construction of the heterogeneous interface effectively promotes the synergistic effect of the catalytically active components Cu 2+1 O and Ag, which enhances the material conductivity, accelerates the interfacial electron transfer, and exposes more active sites, thus improving the performance of ENO 3 RR. Such Cu 2+1 O/Ag-CC manifests a high NH 3 yield of 2.2 mg h -1 cm -2 and a notable ammonia FE of 85.03% at the optimal applied potential of -0.74 V vs RHE in a relatively low concentration of 0.01 M NO 3 - -containing 0.1 M KOH. Moreover, it shows excellent electrochemical stability during the cycle tests. Our study not only provides an efficient catalyst for ammonia electro-synthesis from ENO 3 RR but also an effective strategy for the construction of ENO 3 RR electrocatalysts for electrocatalytic applications.

The electrocatalytic nitrogen reduction reaction (ECNRR) is a sustainable and environmentally friendly method for NH 3 synthesis under environmental conditions relative to the Haber-Bosch process; however, its low selectivity (Faradaic efficiency (FE)) and low NH 3 yield impede the progress. Herein, benefiting from the application of the interface engineering strategy, a multicomponent TiO 2 /Ag/Cu 7 S 4 @Se-CC heterogeneous electrocatalyst with a unique structure was successfully fabricated, generating a unique sandwich structure by using a Ag layer as an electric bridge intercalated between TiO 2 and Cu 7 S 4 , in which the optimized catalyst can accelerate the electron transfer efficiency. Moreover, through the electronic structure adjustment, an electron-deficient region was constructed, which can inhibit the H 2 adsorption but enhance the N 2 adsorption, thereby improving the selectivity and the catalytic activity. Significantly, the FE and NH 3 yield of TiO 2 /Ag/Cu 7 S 4 @Se-CC reached 51.05 ± 0.16% and 39.16 ± 2.31 μg h -1 cm -2 , in which the FE is among the highest non-precious metal-based NRR electrocatalysts in alkaline electrolytes reported. This study provides insight into the rational design and construction of NRR electrocatalysts for electrocatalytic applications.

The combination of the azide bridge and a neutral inner-salt-type dicarboxylate ligand leads to a three-dimensional coordination framework that contains unprecedented azide-bridged tetramanganese(II) clusters and defines a novel self-catenated, eight-connected net of 4(16) x 6(12) topology.