Chloride-Derived Bimetallic Cu-Fe Nanoparticles for High-Selective Nitrate-to-Ammonia Electrochemical Catalysis

Cu-based bimetallic materials have been widely reported as efficient catalysts for electrocatalytic nitrate reduction. However, the faradaic efficiency and selectivity are still far from satisfactory. Herein, Cu-Fe bimetallic nanoalloys with adjustable Cu/Fe ratios are successfully prepared through a reactive mechanical milling approach with CuCl2, FeCl3 and Na as the starting materials. The optimized Cu3Fe exhibits excellent nitrate conversion efficiency of 81.1% and 70.3% ammonia selectivity at −0.7 V vs. RHE within 6 h under 0.1 M Na2SO4 and 100 ppm NO3−. The Fe-introduction-induced upshift of the d-band center is identified to be beneficial for promoting nitrate adsorption on Cu3Fe. Moreover, favorable H generation under the assistance of Fe could effectively accelerate the stepwise hydrogenation during electrocatalytic nitrate reduction, resulting in significantly improved NH4+ selectivity. This work supplies valuable insights for the rational design of transition-metal-based bimetallic catalysts for electrocatalytic nitrate reduction.

Solvent-Induced Growth of Free-Standing 2D Si Nanosheets

2D Si nanomaterials draw great interest owing to their fascinating properties and potential applications in electronic devices, catalysts, and energy storage and conversion devices. However, high-quality and large-scale synthesis of Si nanosheets remains a big challenge, despite the limited reports on their preparations via chemical exfoliation of layered Zintl silicide, magnesiothermic reduction of layered silicon oxide, and chemical vapor deposition. In this work, a facile, solution method to produce free-standing Si nanosheets in high yields and low cost, based on the reaction of commercial magnesium powder with trichlorosilane and tripropylamine in dichloromethane under mild conditions, is reported. The prepared Si nanosheets have an average thickness of ≈2 nm and show photoluminescence. Experiments demonstrate that the key to the formation of Si nanosheets is the use of dichloromethane as a solvent. This method can be used to prepare Si nanosheets in large scale for various potential applications and possibly Si crystals with specific crystal morphology.

One-pot solution synthesis of carbon-coated silicon nanoparticles as an anode material for lithium-ion batteries

Carbon-coated silicon nanoparticles were synthesized via a one-pot solution method, delivering excellent performance in lithium ion batteries.

Fluidized bed reaction towards crystalline embedded amorphous Si anode with much enhanced cycling stability

The fluidized bed reaction route was introduced for the first time to prepare amorphous–crystalline silicon anode materials with excellent cycle stabilities.

Confined silicon nanospheres by biomass lignin for stable lithium ion battery

Biomass lignin, as a significant renewable resource, is one of the most abundant natural polymers in the world. Here, we report a novel silicon-based material, in which lignin-derived functional conformal network crosslinks the silicon nanoparticles via self-assembly. This newly-developed material could greatly solve the problems of large volume change during lithiation/delithiation process and the formation of unstable solid electrolyte interphase layers on the silicon surface. With this anode, the battery demonstrates a high capacity of ∼3000 mA h g^-1, a highly stable cycling retention (∼89% after 100 cycles at 300 mA g^-1) and an excellent rate capability (∼800 mA h g^-1 at 9 A g^-1). Moreover, the feasibility of full lithium-ion batteries with the novel silicon-based material would provide wide range of applications in the field of flexible energy storage systems for wearable electronic devices.