Single‐atom catalysts have demonstrated their superiority over other types of catalysts for various reactions. However, the reported nitrogen reduction reaction single‐atom electrocatalysts for the nitrogen reduction reaction exclusively utilize metal–nitrogen or metal–carbon coordination configurations as catalytic active sites. Here, we report a Fe single‐atom electrocatalyst supported on low‐cost, nitrogen‐free lignocellulose‐derived carbon. The extended X‐ray absorption fine structure spectra confirm that Fe atoms are anchored to the support via the Fe‐(O‐C2)4 coordination configuration. Density functional theory calculations identify Fe‐(O‐C2)4 as the active site for the nitrogen reduction reaction. An electrode consisting of the electrocatalyst loaded on carbon cloth can afford a NH3 yield rate and faradaic efficiency of 32.1 μg h−1 mgcat.−1 (5350 μg h−1 mgFe−1) and 29.3 %, respectively. An exceptional NH3 yield rate of 307.7 μg h−1 mgcat.−1 (51 283 μg h−1 mgFe−1) with a near record faradaic efficiency of 51.0 % can be achieved with the electrocatalyst immobilized on a glassy carbon electrode.

Monodispersed single crystalline R-GaOOH spindles have been prepared via a simple wet-chemical route at 60 °C, in which GaCl 3 was used as the gallium source and ammonia as the alkali. The R-GaOOH spindles obtained at pH values of 10.0 and 11.0 have a hierarchical layered nanostructure and are comprised of many nanoplatelets. The investigation of the products formed at early growth stages indicates that the spindles are formed by a self-assembly process via oriented attachment. During this process, the pH value and the ammonia molecule have great influence on the morphology of the final products. Smooth prism-like R-GaOOH crystals were obtained at a lower pH value of 8.0 when ammonia was used or when ammonia was replaced by ethylenediamine at pH values of 8.0 and 10.0. The single-phase R-Ga 2 O 3 and β-Ga 2 O 3 spindles can be obtained by thermal treatment of the R-GaOOH spindles at 600 and 900 °C, respectively. The morphological characteristics of the pristine R-GaOOH spindles are well maintained in the oxide products in terms of good dispersion, size uniformity and layered nanostructure. The β-Ga 2 O 3 spindle product exhibits a strong blue luminescence emission under the excitation wavelength of 250 nm.

Herein, we demonstrate the design and fabrication of the well-defined triple-shelled Ag@Fe3O4@SiO2@TiO2 nanospheres with burr-shaped hierarchical structures, in which the multiple distinct functional components are integrated wonderfully into a single nanostructure. In comparison with commercial TiO2 (P25), pure TiO2 microspheres, Fe3O4@SiO2@TiO2 and annealed Ag@Fe3O4@SiO2@TiO2 nanocomposites, the as-obtained amorphous triple-shelled Ag@Fe3O4@SiO2@TiO2 hierarchical nanospheres exhibit a markedly enhanced visible light or sunlight photocatalytic activity towards the photodegradation of methylene blue and photoreduction of hexavalent chromium ions in wastewater. The outstanding photocatalytic activities of the plasmonic photocatalyst are mainly due to the enhanced light harvesting, reduced transport paths for both mass and charge transport, reduced recombination probability of photogenerated electrons/holes, near field electromagnetic enhancement and efficient scattering from the plasmonic nanostructure, increased surface-to-volume ratio and active sites in three dimensional (3D) hierarchical porous nanostructures, and improved photo/chemical stability. More importantly, the hierarchical nanostructured Ag@Fe3O4@SiO2@TiO2 photocatalysts could be easily collected and separated by applying an external magnetic field and reused at least five times without any appreciable reduction in photocatalytic efficiency. The enhanced photocatalytic activity and excellent chemical stability, in combination with the magnetic recyclability, make these multifunctional nanostructures promising candidates to remediate aquatic contaminants and meet the demands of future environmental issues.