FeS2@TiO2 nanorods as high-performance anode for sodium ion battery

Efficient Photoelectrocatalytic Reduction of CO2 to Selectively Produce Ethanol Using FeS2/TiO2 p-n Heterojunction Photoelectrodes

Herein, the FeS2/TiO2 p-n heterojunction was first utilized as a photoelectrode for the PEC reduction of CO2 to selectively produce ethanol. The FeS2/TiO2 photoelectrode was fabricated through electrochemical anodization, electrodeposition, and vulcanization methods. The impact of the FeS2 loading amount and applied bias on the PEC performance was investigated. The behavior of photocurrent polarity reverse is observed depending on the FeS2 loading amount, which is related to the energy band structure of the semiconductor/electrolyte interface. The active sites for ethanol production were identified on TiO2 nanotubes rather than on the FeS2 surface. Incorporation of FeS2 not only broadened the visible light absorption range but also formed a p-n heterojunction with TiO2. FeS2/TiO2 with an electrodeposition time of 15 min exhibits the highest ethanol yield of 1170 μmol L-1 cm-2 for 3.5 h of reaction under ultraviolet-visible (UV-Vis) illumination at an applied bias of -0.7 V. Compared to TiO2, FeS2/TiO2 showed significantly higher ethanol yield due to its appropriate loading amount of FeS2 and the synergistic effect of strong UV-Vis light absorption and efficient separation and transfer of charge carriers at the p-n junction.

Recent Advancements in Chalcogenides for Electrochemical Energy Storage Applications

Energy storage has become increasingly important as a study area in recent decades. A growing number of academics are focusing their attention on developing and researching innovative materials for use in energy storage systems to promote sustainable development goals. This is due to the finite supply of traditional energy sources, such as oil, coal, and natural gas, and escalating regional tensions. Because of these issues, sustainable renewable energy sources have been touted as an alternative to nonrenewable fuels. Deployment of renewable energy sources requires efficient and reliable energy storage devices due to their intermittent nature. High-performance electrochemical energy storage technologies with high power and energy densities are heralded to be the next-generation storage devices. Transition metal chalcogenides (TMCs) have sparked interest among electrode materials because of their intriguing electrochemical properties. Researchers have revealed a variety of modifications to improve their electrochemical performance in energy storage. However, a stronger link between the type of change and the resulting electrochemical performance is still desired. This review examines the synthesis of chalcogenides for electrochemical energy storage devices, their limitations, and the importance of the modification method, followed by a detailed discussion of several modification procedures and how they have helped to improve their electrochemical performance. We also discussed chalcogenides and their composites in batteries and supercapacitors applications. Furthermore, this review discusses the subject’s current challenges as well as potential future opportunities.

F-doped zinc ferrite as high-performance anode materials for lithium-ion batteries

Fluorine-doped ZnFe2O4via a quick ice-cold KF/NH4F quenching method effectively improved the electrochemical performance of ZnFe2O4 for LIBs.

Coordination compound-derived La-doped FeS2/N-doped carbon (NC) as an efficient electrocatalyst for oxygen evolution reaction

By annealing/sulfuring of coordination compound (CC) precursors, [LaxFe1-x(H2O)8Fe(CN)6]·2hmt (x = 0, 0.33 and 0.5) (hmt = hexamethylenetetramine), it was synthesized FeS2/N-doped carbon (NC), La-doped FeS2/NC-0.33 and La-doped FeS2/NC-0.5. All of...

Fe-Triazole coordination compound-derived Fe2O3 nanoparticles anchored on Fe-MOF/N-doped carbon nanosheets for efficient electrocatalytic oxygen evolution reaction

Using FeCl₃·6H₂O and 1,2,4-triazole (Htrz) as starting materials, an Fe coordination compound (CC), [FeCl₃(Htrz)₃]·H₂O, was synthesized at room temperature. Fe-CC can be partially transformed into an Fe metal-organic framework (MOF), [FeCl₂(Htrz)], via low-temperature annealing. After sulfurization at 250, 300, and 400 °C, S-doped Fe₂O₃/N-doped carbon (denoted as NC)/Fe-MOF, FeS₂/NC/Fe-MOF, and FeS₂/NC were obtained, respectively. S-doped Fe₂O₃/NC/Fe-MOF shows the best oxygen evolution reaction (OER) catalytic activity in 1 M KOH solution, with overpotentials (η) of 185, 232, and 258 mV required to reach current densities of 10, 30, and 50 mA cm^-2, respectively, outperforming commercial RuO₂ and most transition-metal oxides reported to date; this high performance is associated with the Fe₂O₃ nanoparticles (NPs) anchored on the Fe-MOF/NC nanosheets. The Fe-MOF/NC matrix can act as a support to prevent the agglomeration of Fe₂O₃ NPs. In addition, S-doped Fe₂O₃/NC/Fe-MOF exhibits long-term OER activity at 20 mA cm^-2, which is related to the partial transformation of Fe₂O₃/Fe-MOF into FeOOH. In addition, density functional theory (DFT) calculations show that the rate-determining step of the OER process at the Fe sites of both Fe₂O₃ and FeS₂ is the formation of Fe*-OH, and the Fe₂O₃ sites display a lower Gibbs free energy (ΔG_max) of 1.674 eV and a smaller η value of ∼0.444 V. Bader charge, differential charge density mapping, and density of states (DOS) analysis all reveal more charge accumulation at the Fe sites of FeS₂ than at the Fe sites of Fe₂O₃, which is due to the lower electronegativity of S than of O. As a result, the Fe sites of FeS₂ show weaker affinity for -OH intermediates, giving rise to inferior OER performance compared with Fe₂O₃.