Electrochemical nitrate reduction reaction (NO₃RR) emerges as a sustainable approach for converting residual nitrate pollutants into valuable ammonia under ambient conditions, offering a promising alternative to the energy-intensive Haber–Bosch process. Compared to single-metal-site electrocatalysts, dual-metal-site (DMS) electrocatalysts show synergistic effects between adjacent metal sites, effectively regulating the electronic state and enhancing the catalytic activity and selectivity for NO₃RR with multi-step proton and electron transfers. Further understanding on NO₃RR is of practical significance for design of efficient DMS electrocatalysts. This review aims to systematically investigate the recent advancement of DMS electrocatalysts for NO₃RR to ammonia synthesis, providing new understandings and insights into this catalytic process. The NO₃RR mechanism, artificial intelligence (AI)-driven DMS synthesis, DMS synthesis/characterization, and design of chemical reaction systems are categorized and discussed. DMS electrocatalysts for NO₃RR at the cathode can reduce the energy input for water oxidation, biomass oxidation reactions, and zinc-nitrate batteries, while simultaneously enhancing the yields of anode and cathode products. Finally, the remaining challenges and future perspectives for DMS electrocatalysts in NO₃RR are further discussed. This review provides in-depth guidance for rational design of dual-site electrocatalysts, facilitating practical and sustainable electrochemical processes in the near future.

With the growing demand for clean energy storage, sodium-ion batteries (SIBs) have emerged as a critical alternative to lithium-ion batteries (LIBs) attributable to their resource abundance and cost-effectiveness. Biomass-derived hard carbon (BHC) materials exhibit significant potential as anode materials for SIBs, owing to their renewability, environmental compatibility, and unique microstructures. This review systematically provides a systematic overview of synthetic methods, characterization techniques and regulation strategies of BHC. Then the enhancement mechanism for sodium-ion storage performance was further analyzed and discussed. Despite significant advancements in capacity and cycling stability, some challenges remain, including low initial Coulombic efficiency and insufficient understanding on storage mechanisms at the microscopic level. Future progress in green synthesis processes, multiscale structural design, and investigation under realistic conditions are expected to propel the practical application of BHC toward high-performance and low-cost SIBs, thereby facilitating large-scale storage of sustainable energy.