RESUMEN
Bismuth telluride (Bi2Te3) nanomaterials have attracted considerable attention owing to their intriguing physicochemical properties and wide-ranging potential applications arising from their distinctive layered structure and nanoscale size effects. However, synthesizing sub-100 nm ultra-small Bi2Te3 nanocrystals remains a formidable challenge. To date, there has been little investigation on the performance of these ultra-small Bi2Te3 nanocrystals in sodium-ion batteries (SIBs). This study presents a general strategy for synthesizing ultra-small Bi2Te3 nanocrystals on reduced graphene oxide (Bi2Te3/rGO) through a nanoconfinement approach. First-principles calculations and electrochemical kinetic studies confirm that the ultra-small Bi2Te3/rGO composite material can effectively mitigate volumetric expansion, preserve electrode integrity, and enhance electron transfer, Na-ion adsorption, and diffusion capacity. As a result, the Bi2Te3/rGO electrode demonstrates a remarkable initial specific capacity of 521 mA h g-1 at 0.1 A g-1, showcasing outstanding rate behaviour and long-lasting cycle life exceeding 800 cycles at 1 A g-1 while preserving exceptional rate properties. The function of the battery is indicated by ex situ TEM and XPS findings, which propose a conventional dual mechanism involving conversion and alloying. This work paves the way for rapid advancements in Bi2Te3-based SIB anodes while contributing to our understanding of sodium ion storage mechanisms.
RESUMEN
For the simultaneous photocatalytic reduction of hexavalent chromium (Cr(VI)) and the degradation of rhodamine B (RhB), directional charge-transfer channels and efficient separation of photogenerated holes and electrons are important. Herein, a Z-scheme heterojunction photocatalyst, protonated g-C3N4/BiVO4 decorated with wood flour biochar (pCN/WFB/BiVO4), was prepared through a hydrothermal reaction and electrostatic self-assembly for Cr(VI) photoreduction and RhB photodegradation. The morphological features, crystalline structure, chemical composition, optical properties, specific surface area, and photoelectrochemical properties of the prepared samples were investigated. The pCN/WFB/BiVO4 photocatalyst exhibited superior removal performance when used to remove Cr(VI) and RhB separately or RhB-Cr(VI) system. The biochar bridge served as a charge-transfer channel between two semiconductors, and the electrons in protonated g-C3N4 (pCN) and BiVO4 achieved a charge balance. This led to the formation of a Z-scheme heterojunction, fast photogenerated charge separation, and a powerful redox ability. The pCN/WFB/BiVO4 photocatalyst provides new insight into the mechanisms responsible for boosting multicomponent photocatalytic reactions, while constituting a promising candidate for wastewater treatment.