Sai Zhang

Electrochemical reduction of nitrate to ammonia holds a great potential to replace the Haber–Bosch process for green NH ₃ synthesis, which promotes modern agricultural and carbon-free energy systems.

Electrochemical nitrate reduction to ammonia (eNO3–RR) offers a sustainable route for nitrogen recovery and wastewater remediation, yet its efficiency at high reaction potentials is severely constrained by sluggish proton coupling of *NOx intermediates and the competitive hydrogen evolution reaction (HER). Herein, we report a local built-in-electric field (LBIEF)-modulated FeNi/NiFe2O4 heterojunction that overcomes these kinetic bottlenecks through interfacial electronic polarization and spatially coordinated dual-site catalysis. The optimized LBIEF induces spontaneous charge redistribution, generating electron-deficient Fe(II) sites that strengthen nitrate and *NOx adsorption and electron-rich Ni0 sites that promote efficient *H formation and transfer. This synergistic charge bifurcation significantly lowers the energy barrier of the rate-determining *NO to *NOH hydrogenation step, enabling near-unity hydrogen utilization (97.9%) and suppressing parasitic hydrogen evolution. As a result, the FeNi/NiFe2O4 catalyst achieves an exceptional NH3 yield of 91.2 ± 2.8 mg h–1 mgcat–1 with a Faradaic efficiency (FE) of 94.5 ± 1.6% at −1.4 V vs. RHE, alongside 96.3% nitrate removal and 98.8% NH3 selectivity, while maintaining stability over 200 h of continuous operation. Operando spectroscopy and density functional theory reveal that LBIEF-mediated electronic polarization governs intermediate adsorption, hydrogen transfer, and reaction pathway selectivity. This work establishes LBIEF engineering as a general strategy to synchronize nitrate activation and hydrogenation, offering a mechanistic blueprint for next-generation electrocatalysts for sustainable nitrogen valorization.

We present a novel ZnO/CdS (HP) photocatalyst by coupling hollow spherical structure and Z -scheme heterojunction, which creates more active sites and enhances charge separation, significantly promoting photocatalytic hydrogen production.

We present a A/R-TiO ₂ /CuO _x electrocatalyst by coupling dual electric fields and hollow porous structures, which boosts the NO ₃ ⁻ enrichment and conversion to ammonia.

The complete removal of tetracycline residuals under visible light still is a challenging task because of their robust ring structure. To tackle this issue, we explore a novel Bi₂O₃-sensitized TiO₂ visible-light photocatalyst by combining p–n heterojunction with hollow structure. The hollow TiO₂/Bi₂O₃ photocatalyst manifests excellent photocatalytic performance and recyclability toward the complete degradation (100%) of antibiotics under visible light (λ > 420 nm) because of the synergistic effect of p–n heterojunction and hollow structure, successfully overcoming the challenge of the incomplete removal of antibiotics over almost all of the reported visible-light photocatalysts. Additionally, the effects of inorganic ions, pH value, water matrix, and outdoor light on the degradation of tetracyclines were investigated with many details. Notably, the degradation pathways and mechanism of tetracycline were revealed according to trapping experiments, HPLC-MS, and photoelectrochemical characterizations. Therefore, this work provides a new insight into developing visible-light photocatalysts with excellent photocatalytic performances for the complete removal of other refractory contaminants.