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The rapid detection of uranium in water environment is of great significance for water purification and uranium recovery. In this work, ultrathin nickel hydroxide (Ni(OH)2) nanosheets was in-situ growth on carbon nanotubes (CNTs) to form Ni(OH)2@CNTs electrode for uranyl ion (UO22+) detection. The as-prepared Ni(OH)2@CNTs shows good sensitivity in the electrolyte containing UO22+ with the limit of detection of about 8.603 ppb. Moreover, the Ni(OH)2@CNTs also exhibits significant selectivity for UO22+ in complex wastewater with several interfering cations and anions. This work provides a novel Ni(OH)2@CNTs electrode for UO22+ detection from uranium-containing water. [ABSTRACT FROM AUTHOR]

The rational design of materials at atomic scale as efficient and stable electrocatalysts for hydrogen evolution reaction (HER) is critical for energy conversion. Herein, we report a novel hybrid nanostructure with iridium (Ir) and cobalt (Co) atomic pair configuration anchored in porous nitrogen-doped carbon (pNC) nanosheets (denoted as IrCo-pNC) for electrocatalytic HER. Experimental investigations and theoretical calculations reveal that the interaction between Ir and Co species in pNC promotes electron accumulation and depletion around isolated Ir and Co atoms, respectively, resulting in a local asymmetry electron density distribution. Density functional theory calculations also suggest that the electrons transfer from Co to adjacent Ir atom causing the down shift of the d-band center of Ir 5d in IrCo-pNC catalyst, thus optimizing the adsorption of hydrogen on Ir sites. The as-prepared IrCo-pNC exhibits significant HER performance with an overpotential of 21 mV to achieve a current density of 10 mA·cm−2 in 0.5 M H2SO4. This work provides insight into the role of asymmetry electron density distribution in nanomaterials in regulating HER electrocatalysis. [ABSTRACT FROM AUTHOR]

Efficient removal of uranium from wastewater is of great significance to the environment and human health. Herein, a novel electrode composed of carbon felt-anchored phosphorus-functionalized tungsten trioxide nanosheets (P-WO 3 @CF) was designed for electrochemical extraction of UO 2 2+ from uranium-containing wastewater. The induced P in WO 3 @CF not only improves the conductivity to accelerate electron transfer, but also offers surface P O species to capture UO 2 2+ for subsequent electrochemical reduction. Besides, the decoration of WO 3 and P-WO 3 greatly enhanced the hydrophilicity of electrode. As a result, the required voltage was significantly reduced for the electrochemical extraction of UO 2 2+ by using P-WO 3 @CF. The extraction efficiency of UO 2 2+ reached 98.8 % within 240 min at −2 V (vs. Ag/AgCl) by the P-WO 3 @CF electrode. Moreover, the P-WO 3 @CF electrode also exhibited significant antijamming capability for UO 2 2+ extraction in complex aqueous environment with several interfering metal ions. This work provides a new strategy to design novel electrode for efficient extraction of uranium from aqueous solutions. [Display omitted] • A novel P-WO 3 @CF electrode was designed and synthesized for UO 2 2+ removal. • The hydrophilicity and electronic structures of WO 3 were significantly regulated. • U(VI) was efficiently reduced by P-WO 3 @CF via electrochemical reduction. • The P-WO 3 @CF exhibits high selectivity for UO 2 2+ removal form simulated wastewater. [ABSTRACT FROM AUTHOR]