The electrocatalytic nitrogen reduction reaction (e-NRR) is a promising alternative method for the Haber–Bosch process. However, it still faces many challenges in searching for high activity, stability, and selectivity catalysts and ascertaining the catalytic mechanism with complete insight. Here, a series of graphene-based N-bridged dual-atom catalysts (M1-N-M2/NC) are systematically investigated via first-principle calculation and a high-throughput screening strategy. The result unveils that N₂ adsorption on M1-N-M2/NC in bridge-on adsorption mode can effectively break the scaling relationship on single-atom catalysts (SACs). Moreover, V-N-Ru/NC and V-N-Os/NC are systematically screened out as promising e-NRR catalysts, with extremely low limiting potentials of −0.20 and −0.18 V, respectively. Furthermore, the adsorption site competition between *N₂ and *H, as well as the competitive twin reactions of hydrogen evolution reaction (HER) on intermediates (N_nH_m) during the e-NRR process, is systematically evaluated to form a remodeling insight for the reactions in mechanism, and the e-NRR of new proposed dual-atom catalysts (DACs) is strategically optimized for its high-efficiency performance potential via our remolding insight in e-NRR mechanism. This work provides new ideas and insights for the design and mechanism of e-NRR catalysts and an effective strategy for rapidly screening highly efficient e-NRR catalysts.

Photoreduction of hexavalent uranium (U(VI)) by semiconductor provides a novel and effective avenue for uranium extraction. Unfortunately, the traditional metal oxide and sulfide semiconductors suffer from the lack of confinement sites to U(VI), which resulted in the long period (~ 1 h) to achieve a high U(VI) extraction efficiency of > 90%. Herein, we successfully constructed WS₂ nanosheets and created in-situ oxidized domains on the surfaces (O-WS₂) to promote the uranium extraction and the corresponding removal kinetics. In this system, the O_7.7-WS₂ nanosheets exhibited a considerable U(VI) extraction efficiency of > 90% within 20 min in 8 mg·L^–1 U(VI)-containing solution, which represented the highly efficient U(VI) removal performance. In 200 mg·L^–1 U(VI)-containing solution, the O_7.7-WS₂ nanosheets exhibited an extraction capacity of 652.4 mg·g^–1. The mechanism study revealed that the oxidized surface tended to trap hydrogen atom and in-situ form hydroxyl groups in defect sites. Evidenced by a series of experiment, such as kinetic isotope effect, ¹H nuclear magnetic resonance (NMR) spectra, and X-ray absorption near-edge structure (XANES) spectra, the in-situ formed hydroxyl groups participated in the uranium reduction, which dramatically enhanced uranium extraction kinetics and efficiency.

Photocatalytic reduction of U(VI) represents a novel and effective manner for the removal of U(VI) pollutant from radioactive wastewater. Herein, we successfully incorporated hydrogen into VO₂ nanosheets, which strengthened the interaction between VO₂ and U(VI), thereby achieving a highly active and stable photocatalyst for U(VI) reduction. With the increase of H content in hydric VO₂ (H_x-VO₂) nanosheets, the bandgap shrank from 2.29 to 1.66 eV, whereas the position of conduction bands remained more negative than the reduction potential of U(VI)/U(IV) (0.41 V vs. NHE). When irradiated by simulated sunlight, the U(VI) removal efficiency over H_0.613-VO₂ nanosheets reached up to 95.4% within 90 min, which largely outperformed 28.3% of pristine VO₂ nanosheets. The mechanistic study demonstrated that the hydroxylated surface gave rise to the balanced O confinement sites in VO₂ (011), leading to the stabilized adsorption configuration and increased binding strength of UO₂²⁺ on H_x-VO₂ nanosheets.