Electrocatalytic NO reduction reaction offers a sustainable route to achieving environmental protection and NH₃ production targets as well. In this work, a class of dealloyed Ti₆₀Cu₃₃Mn₇ ribbons with enough nanoparticles for the high-efficient NO reduction reaction to NH₃ is fabricated, reaching an excellent Faradaic efficiency of 93.2% at –0.5 V vs reversible hydrogen electrode and a high NH₃ synthesis rate of 717.4 μmol·h^–1·mg_cat.^–1 at –0.6 V vs reversible hydrogen electrode. The formed nanoparticles on the surface of the catalyst could facilitate the exposure of active sites and the transportation of various reactive ions and gases. Meanwhile, the Mn content in the TiCuMn ribbons modulates the chemical and physical properties of its surface, such as modifying the electronic structure of the Cu species, optimizing the adsorption energy of N* atoms, decreasing the strength of the NO adsorption, and eliminating the thermodynamic energy barrier, thus improving the NO reduction reaction catalytic performance. Moreover, a Zn-NO battery was fabricated using the catalyst and Zn plates, generating an NH₃ yield of 129.1 µmol·h^–1·cm^–2 while offering a peak power density of 1.45 mW·cm^–2.

● Formate addition led to more abundant and active anammox bacteria in community.

The addition of traditional carbon sources (e.g., acetate) could favor heterotrophic overgrowth in partial denitrification coupled with anammox (PD–A) systems, thus hindering the performance and stability of this novel wastewater nitrogen removal technology. Therefore, it is necessary to develop an effective, environmentally friendly, and inexpensive alternative. This study demonstrated the potential of formate to enhance the performance and community stability of PD–A under mainstream conditions. In a laboratory-scale biofilm reactor, formate addition (COD/NO₃^––N = 1.75) improved nitrogen removal efficiency (from 72.1 ± 3.5% to 81.7 ± 2.7%), EPS content (from 106.3 ± 8.1 to 163.0 ± 15.5 mg/gVSS) and increased anammox bacteria growth (predominantly Candidatus Brocadia, from 29.5 ± 0.7% to 34.5 ± 5.4%) while maintaining stable heterotrophs dominated by methylotrophic Desulfobacillus. FISH–NanoSIMS revealed a formate uptake using Ca. Brocadia and Desulfobacillus, with Ca. Brocadia being the major contributor to partial nitrate reduction to nitrite. Desulfobacillus can synthesize diverse hydrophobic amino acids and provide key nutrients for Ca. Brocadia. To achieve comparable nitrogen removal, the cost of the formate-driven PD–A process should be 11.2% lower than that of acetate. These results greatly enrich our understanding of C1 metabolism represented by formate in anammox communities and its application in the context of coupling partial denitrification–anammox toward enhanced nitrogen removal in global wastewater treatment systems.

The fabrication of heterojunction catalysts is an effective strategy to enhance charge separation efficiency, thus boosting the performance of photocatalysts. This work presents the synthesis and investigation of a novel KNbO₃/Bi₄O₅Br₂ heterostructure catalyst for photocatalytic N₂–to–NH₃ conversion under light illumination. While morphology analysis revealed KNbO₃ microcubes embedded within Bi₄O₅Br₂ nanosheets, the composite exhibited no significant improvement in specific surface area or optical property compared to Bi₄O₅Br₂ due to the relatively wide band gap and low surface area of KNbO₃. The main contribution lies in the enhanced separation efficiency of photogenerated electrons and holes. Besides, the band structure analysis suggests that KNbO₃ and Bi₄O₅Br₂ exhibit suitable band potentials to form a type II heterojunction. Benefiting from the higher Fermi level of KNbO₃ than Bi₄O₅Br₂, the electron drift at the contact region thus occurs and leads to the formation of a built-in electric field with the direction from KNbO₃ to Bi₄O₅Br₂, accelerating electron migration and improving the operational efficiency of the photocatalysts. Consequently, the KNbO₃/Bi₄O₅Br₂ catalyst shows an increased photoactivity, achieving an NH₃ generation rate 1.78 and 1.58 times those of KNbO₃ and Bi₄O₅Br₂, respectively. This work may offer valuable insights for the design and synthesis of heterojunction composite photocatalysts.

Layered double hydroxides have demonstrated great potential for the oxygen evolution reaction, which is a crucial half-reaction of overall water splitting. However, it remains challenging to apply layered double hydroxides in other electrochemical reactions with high efficiency and stability. Herein, we report two-dimensional multifunctional layered double hydroxides derived from metal-organic framework sheet precursors supported by nanoporous gold with high porosity, which exhibit appealing performances toward oxygen/hydrogen evolution reactions, hydrazine oxidation reaction, and overall hydrazine splitting. The as-prepared catalyst only requires an overpotential of 233 mV to reach 10 mA·cm^–2 toward oxygen evolution reaction. The overall hydrazine splitting cell only needs a cell voltage of 0.984 V to deliver 10 mA·cm^–2, which is far more superior than that of the overall water splitting system (1.849 V). The appealing performances of the catalyst can be contributed to the synergistic effect between the metal components of the layered double hydroxides and the supporting effect of the nanoporous gold substrate, which could endow the sample with high surface area and excellent conductivity, resulting in superior activity and stability.