Bifunctional N-Doped Tungsten Trioxide Microspheres as Electrode Materials for Lithium-Ion Batteries and Direct Methanol Fuel Cells

Abstract

Oxygen vacancies (OVs) have emerged as an efficient strategy to modulate the electronic structures, conductivity, and electrochemical properties of WO3. However, OVs are easily absorbed by water molecules or oxygen atoms, resulting in the poor stability of its electrocatalytic reaction. In the present work, we have demonstrated that nitrogen doping provides an alternative to improve the electrochemical properties of WO3, which plays a series of roles in reducing the band gap, improving the electron mobility, accelerating the Li+ ion diffusion, and providing more active sites for catalytic reactions. Consequently, N-doped WO3 microspheres exhibit low discharge–charge voltage gaps and high capacity retention as well as exceptional rate performance when used as anode materials for lithium-ion batteries (LIBs). Furthermore, the as-prepared Pt/N-WO3 catalyst also exhibits excellent electrocatalytic properties toward methanol electro-oxidation (MOR) including high activity, strong poison tolerance, and outstanding long-term stability owing to the synergetic effects between Pt and N-WO3.

Disordered but Efficient: Understanding the Role of Structure and Composition of the Co–Pt Alloy on the Electrocatalytic Methanol Oxidation Reaction

“…are being projected as the most promising alternatives, especially with regards to their ability to withstand carbon monoxide mediated surface poisoning. More specifically, in the case of DMFCs bimetallic Pt-alloys, such as Ru x Pt 1– x , Cu x Pt 1– x , Co x Pt 1– x , etc., have been reported to show good tolerance toward CO poisoning. − Although alloying of two or more metals is a very attractive approach for modifying the electronic and geometric structure of a material and to enhance its activity and stability, not much is understood regarding the mechanism of their enhanced activities (structure–property correlation). Only some empirical guidelines, such as (a) usage of M–Pt alloys as catalysts (where M stands for different transition metals), (b) preparing materials where Pt is present either as a monolayer on the surface of another metal or Pt is present just below a monolayer of another metal, (c) preparation of core–shell architectures where again one or few layers of Pt are coated as a shell on another cheap metal, and (d) making an alloy of M–Pt type and then dealloying to remove the other metal without losing the structure and strain as present in the original alloy, are being suggested as approaches to improve Pt activity. − It is evident from the above list that the arrangement and the relative position of Pt with respect to the other metal atom in the alloy appear to play significant roles in influencing the catalytic activities of these bimetallic systems.…”

Electrocatalytic Upgrading of Plastic and Biomass‐Derived Polyols to Formamide under Ambient Conditions

“…As shown in Figure 3c, during water oxidation (without EG and NH 3 ), hydroxyl radical (DMPO‐OH) was detected. We proposed that W atoms served as the active sites for water dissociation to produce hydroxyl radicals [18] …”

“…We proposed that W atoms served as the active sites for water dissociation to produce hydroxyl radicals. [18] . During NH 3 oxidation (without EG), a signal from a DMPOÀ N spin adduct appeared, indicating the formation of a nitrogen radicals (*NH 2 ).…”

An Efficient and Durable Electrocatalyst Based on Strongly Coupled Pt Nanoparticles on CeO2 Microspheres for CO-Resilient Methanol Oxidation

“…To tackle the above-mentioned challenges, substantial research efforts have been devoted to the development of alternative electrocatalysts. The most promising approaches adopted for this purpose are alloying Pt with other transition metals, such as Co, Cu, Ni, Ru, etc., and embedding the Pt catalyst with metal oxide supports, such as TiO 2 , SnO 2 , SiO 2 , CeO 2, WO 3 /W 18 O 49, , etc. While both strategies have worked well for improving the performance of catalytic electrodes, the latter strategy seems to be more advantageous considering the performance, stability, and extent of CO tolerance of the metal-oxide-supported Pt catalysts.…”