Enhanced Photocatalytic Water Splitting by Plasmonic TiO₂–Fe₂O₃ Cocatalyst under Visible Light Irradiation

In this study, we introduce a plasmonic TiO₂–Fe₂O₃ cocatalyst photoelectrode to improve the water-splitting process. The absorption of incident photons and the separation rate of photogenerated electron–hole pairs are enhanced due to the broadband absorption and strong electric field of the composite formed from these two metal oxide semiconductors and plasmonic silver nanoparticles (Ag NPs). Plasmonic TiO₂–Fe₂O₃ cocatalyst photoelectrodes were fabricated using a precipitation and solution processing method. Under visible light irradiation, a photocurrent that is 20 times higher than that of pure Fe₂O₃ was observed using an optimized ratio of the plasmonic TiO₂–Fe₂O₃/Ag cocatalyst. The mechanism for this enhancement in the plasmonic cocatalyst system was investigated using different structural configurations of the photoelectrode. Both the crystallinity and absorption band edge of the TiO₂–Fe₂O₃ cocatalyst were characterized using X-ray diffraction (XRD) and ultraviolet–visible absorption spectroscopy (UV–vis). Furthermore, the spatial distribution of the photocurrent was investigated using this plasmonic cocatalyst system

Additional file 1: of Photocatalytic Activities Enhanced by Au-Plasmonic Nanoparticles on TiO2 Nanotube Photoelectrode Coated with MoO3

Supporting information. (DOCX 1074 kb

Comparative Study on the Morphology-Dependent Performance of Various CuO Nanostructures as Anode Materials for Sodium-Ion Batteries

In this work, CuO samples with three different nanostructures, i.e., nanoflakes, nanoellipsoids, and nanorods, are successfully synthesized by a facile and environmentally friendly hydrothermal approach based on the use of different structure directing agents. The morphological influence on the anodic electrochemical performances, such as capacity, cycling stability, rate capability, and diffusion coefficient measurements of these different CuO nanostructures is comparatively investigated for sodium-ion batteries. The capacity and cycling stability are higher for the CuO nanorods (CuO-NRs) based electrode as compared to the cases of CuO nanoellipsoids (CuO-NEs) and CuO nanoflakes (CuO-NFs). At a low current density of 25 mA g^–1, the CuO-NRs based electrode exhibits an excellent reversible capacity of 600 mA h g^–1. It also exhibits a capacity of 206 mA h g^–1 after 150 cycles with a capacity retention of 73% even at a higher current density of 1000 mA g^–1. The exceptional performance of CuO-NRs is attributable to its slim nanorod morphology with a smaller particle size that provides a short diffusion path and the maximized surface area facilitating good diffusion in electrolytes, ensuring good electronic conductivity and cycling stability. The comparative analysis of these materials can provide valuable insights to design hierarchical nanostructures with distinct morphology to achieve better materials designed for sodium-ion batteries

Electrolyte Optimization for Enhancing Electrochemical Performance of Antimony Sulfide/Graphene Anodes for Sodium-Ion Batteries–Carbonate-Based and Ionic Liquid Electrolytes

The electrolyte is a key component in determining the performance of sodium-ion batteries. A systematic study is conducted to optimize the electrolyte formulation for a Sb₂S₃/graphene anode, which is synthesized via a facile solvothermal method. The effects of solvent composition and fluoroethylene carbonate (FEC) additive on the electrochemical properties of the anode are examined. The propylene carbonate (PC)-based electrolyte with FEC can ensure the formation of a reliable solid-electrolyte interphase layer, resulting in superior charge–discharge performance, compared to that found in the ethylene carbonate (EC)/diethyl carbonate (DEC)-based electrolyte. At 60 °C, the carbonate-based electrolyte cannot function properly. At such an elevated temperature, however, the use of an <i>N</i>-propyl-<i>N</i>-methylpyrrolidinium bis­(fluorosulfonyl)­imide ionic liquid electrolyte is highly promising, enabling the Sb₂S₃/graphene electrode to deliver a high reversible capacity of 760 mAh g^–1 and retain 95% of its initial performance after 100 cycles. The present work demonstrates that the electrode sodiation/desodiation properties are dependent significantly on the electrolyte formulation, which should be optimized for various application demands and operating temperatures of batteries

Electrolyte Optimization for Enhancing Electrochemical Performance of Antimony Sulfide/Graphene Anodes for Sodium-Ion Batteries–Carbonate-Based and Ionic Liquid Electrolytes

The electrolyte is a key component in determining the performance of sodium-ion batteries. A systematic study is conducted to optimize the electrolyte formulation for a Sb₂S₃/graphene anode, which is synthesized via a facile solvothermal method. The effects of solvent composition and fluoroethylene carbonate (FEC) additive on the electrochemical properties of the anode are examined. The propylene carbonate (PC)-based electrolyte with FEC can ensure the formation of a reliable solid-electrolyte interphase layer, resulting in superior charge–discharge performance, compared to that found in the ethylene carbonate (EC)/diethyl carbonate (DEC)-based electrolyte. At 60 °C, the carbonate-based electrolyte cannot function properly. At such an elevated temperature, however, the use of an <i>N</i>-propyl-<i>N</i>-methylpyrrolidinium bis­(fluorosulfonyl)­imide ionic liquid electrolyte is highly promising, enabling the Sb₂S₃/graphene electrode to deliver a high reversible capacity of 760 mAh g^–1 and retain 95% of its initial performance after 100 cycles. The present work demonstrates that the electrode sodiation/desodiation properties are dependent significantly on the electrolyte formulation, which should be optimized for various application demands and operating temperatures of batteries

Nitrogen-Doped Graphene Sheets Grown by Chemical Vapor Deposition: Synthesis and Influence of Nitrogen Impurities on Carrier Transport

A significant advance toward achieving practical applications of graphene as a two-dimensional material in nanoelectronics would be provided by successful synthesis of both n-type and p-type doped graphene. However, reliable doping and a thorough understanding of carrier transport in the presence of charged impurities governed by ionized donors or acceptors in the graphene lattice are still lacking. Here we report experimental realization of few-layer nitrogen-doped (N-doped) graphene sheets by chemical vapor deposition of organic molecule 1,3,5-triazine on Cu metal catalyst. When reducing the growth temperature, the atomic percentage of nitrogen doping is raised from 2.1% to 5.6%. With increasing doping concentration, N-doped graphene sheet exhibits a crossover from p-type to n-type behavior accompanied by a strong enhancement of electron–hole transport asymmetry, manifesting the influence of incorporated nitrogen impurities. In addition, by analyzing the data of X-ray photoelectron spectroscopy, Raman spectroscopy, and electrical measurements, we show that pyridinic and pyrrolic N impurities play an important role in determining the transport behavior of carriers in our N-doped graphene sheets