An insight into the effect of g-C3N4 support on the enhanced performance of ZnS nanoparticles as anode material for lithium-ion and sodium-ion batteries

Unveiling the photocatalytic potential of graphitic carbon nitride (g-C3N4): a state-of-the-art review

Graphitic carbon nitride (g-C3N4)-based materials have emerged as promising photocatalysts due to their unique band structure, excellent stability, and environmental friendliness. This review provides a comprehensive and in-depth analysis of the current state of research on g-C3N4-based photocatalysts. The review summarizes several strategies to improve the photocatalytic performance of pristine g-C3N4, e.g., by creating heterojunctions, doping with non-metallic and metallic materials, co-catalyst loading, tuning catalyst morphology, metal deposition, and nitrogen-defect engineering. The review also highlights the various characterization techniques employed to elucidate the structural and physicochemical features of g-C3N4-based catalysts, as well as their applications of in photocatalytic degradation and hydrogen production, emphasizing their remarkable performance in pollutants' removal and clean energy generation. Furthermore, this review article investigates the effect of operational parameters on the catalytic activity and efficiency of g-C3N4-based catalysts, shedding light on the key factors that influence their performance. The review also provides insights into the photocatalytic pathways and reaction mechanisms involving g-C3N4 based photocatalysts. The review also identifies the research gaps and challenges in the field and presents prospects for the development and utilization of g-C3N4-based photocatalysts. Overall, this comprehensive review provides valuable insights into the synthesis, characterization, applications, and prospects of g-C3N4-based photocatalysts, offering guidance for future research and technological advancements in this rapidly growing field.

ZnS/CoS@C Derived from ZIF-8/67 Rhombohedral Dodecahedron Dispersed on Graphene as High-Performance Anode for Sodium-Ion Batteries

Metal sulfides are highly promising anode materials for sodium-ion batteries due to their high theoretical capacity and ease of designing morphology and structure. In this study, a metal-organic framework (ZIF-8/67 dodecahedron) was used as a precursor due to its large specific surface area, adjustable pore structure, morphology, composition, and multiple active sites in electrochemical reactions. The ZIF-8/67/GO was synthesized using a water bath method by introducing graphene; the dispersibility of ZIF-8/67 was improved, the conductivity increased, and the volume expansion phenomenon that occurs during the electrochemical deintercalation of sodium was prevented. Furthermore, vulcanization was carried out to obtain ZnS/CoS@C/rGO composite materials, which were tested for their electrochemical properties. The results showed that the ZnS/CoS@C/rGO composite was successfully synthesized, with dodecahedrons dispersed in large graphene layers. It maintained a capacity of 414.8 mAh g-1 after cycling at a current density of 200 mA g-1 for 70 times, exhibiting stable rate performance with a reversible capacity of 308.0 mAh g-1 at a high current of 2 A g-1. The excellent rate performance of the composite is attributed to its partial pseudocapacitive contribution. The calculation of the diffusion coefficient of Na+ indicates that the rapid sodium ion migration rate of this composite material is also one of the reasons for its excellent performance. This study highlights the broad application prospects of metal-organic framework-derived metal sulfides as anode materials for sodium-ion batteries.

Molecular precursor mediated selective synthesis of phase pure cubic InSe and hexagonal In2Se3 nanostructures: new anode materials for Li-ion batteries

Indium selenides (InSe and In₂Se₃) have earned a special place among the 2D layered metal chalcogenides owing to their nontoxic nature and favourable carrier mobility. Additionally, they are also being projected as next generation battery anodes with high theoretical lithium-ion storage capacities. While the development of indium selenide-based batteries is still in its embryonic stage, a simple and easily scalable synthetic pathway to access these materials is highly desirable for energy storage applications. This study reports a controlled synthetic route to nanometric cubic InSe and hexagonal In₂Se₃ materials through proper choice of coordinating solvents from a structurally characterized air and moisture stable single source molecular precursor: tris(4,6-dimethyl-2-pyrimidylselenolato)indium(III). The crystal structure, phase purity, composition, morphology and band gap of the nanomaterials were thoroughly evaluated by pXRD, energy dispersive X-ray spectroscopy (EDS), electron microscopy (SEM and TEM), and diffuse reflectance spectroscopy (DRS), respectively. The pristine InSe and In₂Se₃ nanostructures have been employed as anode materials in lithium-ion batteries (LIBs). Both the cells deliver reasonably high initial discharge capacities with a cyclability of 200 and 620 cycles for cubic InSe and hexagonal In₂Se₃ respectively with ∼100% coulombic efficiency.

Constructing Z-scheme g-C3N4/TiO2 heterostructure for promoting degradation of the hazardous dye pollutants

The use of dyes and segments has increased widely in recent years, but it poses a serious health risk to ecosystems. In this work, TiO₂ and two-dimensional g-C₃N₄ nanosheets (g-CN) were fabricated through co-precipitation and thermal polymerization technique, respectively. The g-CN-TiO₂ photocatalyst (1: 3, 2: 2, 3: 1) in various weight percentages was prepared using a simple impregnation process. The photocatalytic behaviour of the g-CN, TiO₂ NPs, and different weight percentages of g-CN-TiO₂ photocatalyst was evaluated against methylene blue (MB) dye under UV-visible light illumination. Compared to pristine and other weight percentages of the g-CN-TiO₂ nanocomposite, the optimized g-CN-TiO₂ nanocomposite (3:1) showed promoted performance against MB dye. The enriched catalytic efficiency can be accredited to the low amount of TiO₂ nanoparticles deposited on gCN nanosheets, possibly due to the boosted transport properties of the electron-hole pairs. The enriched photocatalytic behaviour can be attributed to the development of the Z-scheme system between TiO₂ and g-CN. The current study is an outstanding demonstration of the development of maximum catalytic efficiency for destroying hazardous chemical dyes.

Improved Li storage performance of SnO nanodisc on SnO2quantum dots embedded carbon matrix

Li-ion batteries with conversion type anode are attractive choice, for electric vehicles and portable electronic devices, because of their high theoretical capacity and cycle stability. On the contrary, enormous volume change during lithiation/delithiation and irreversible conversion reaction limits use of such anodes. To overcome these challenges, incorporating nano-sized SnO_xon flexible carbonaceous matrix is an efficient approach. A facile and scalable fabrication of SnO nanodisc decorated on SnO₂quantum dots embedded carbon (SnO_x@C) is reported in the present study. Detailed structural and morphological investigation confirms the successful synthesis of SnO_x@C composite with 72.3 wt% SnO_xloading. The CV profiles of the nanocomposite reveal a partial reversibility of conversion reaction for the active materials SnO_x. Such partial reversible conversion enhances the overall capacity of the nanocomposite. It delivers a very high discharge capacity of 993 mAh g^-1at current density of 0.05 A g^-1after 200 cycles; which is 2.6 times higher than that of commercial graphitic anode (372 mAh g^-1) and very close to the calculated capacity of the SnO_x@C composite. This unique nanocomposite remarkably improves Li storage performance in terms of reversible capacity, rate capability and cycling performance. It is established that such engineered anode can efficiently reduce the electrode pulverization and in turn make conversion reaction of tin partially reversible.

An insight into the sodium-ion and lithium-ion storage properties of CuS/graphitic carbon nitride nanocomposite

Metal sulfides are gaining prominence as conversion anode materials for lithium/sodium ion batteries due to their higher specific capacities but suffers from low stability and reversibility issues. In this work, the electrochemical properties of CuS anode material has been successfully enhanced by its composite formation using graphitic carbon nitride (g-C3N4). The CuS nanoparticles are distributed evenly in the exfoliated g-C3N4 matrix rendering higher electronic conductivity and space for volume alterations during the repeated discharge/charge cycles. The 0.8CuS:0.2g-C3N4 composite when used as an anode for lithium ion coin cell exhibits a reversible capacity of 478.4 mA h g-1 at a current rate of 2.0 A g-1 after a run of 1000 cycles which is better than that reported for CuS composites with any other carbon-based matrix. The performance is equally impressive when 0.8CuS:0.2g-C3N4 composite is used as an anode in a sodium ion coin cell and a reversible capacity of 408 mA h g-1 is obtained at a current rate of 2.0 A g-1 after a run of 800 cycles. A sodium ion full cell with NVP cathode and 0.8CuS:0.2g-C3N4 composite anode has been fabricated and cycled for 100 runs at a current rate of 0.1 A g-1. It can be inferred that the g-C3N4 matrix improves the ion transfer properties, alleviates the volume alteration happening in the anode during the discharge/charge process and also helps in preventing the leaching of polysulfides generated during the electrochemical process.

Molten salt synthesis of KCl-preintercalated C3N4 nanosheets with abundant pyridinic-N as a superior anode with 10 K cycles in lithium ion battery

The graphitic carbon nitride is considered as the promising anode of lithium ion battery due to its high theoretical capacity (>1000 mAh g^-1) and easy synthesis method. But the electrochemical inactivity and the structural collapse during cycles lead to its poor electrochemical performance in practice. Here, an interesting molten salt method is used to obtain the KCl-preintercalated carbon nitride nanosheets with abundant N vacancies and pyridinic-N. The KCl as a prop enhances the interlayer distance and the structural stability. And the N vacancy and the pyridinic-N increase the conductivity, the active sites and the reversibility of Li⁺ storage. Thus, the optimized electrode shows a higher specific discharge capacity (389 mAh g^-1 at 0.1 A g^-1) and a longer cyclic life (66% capacity retention after 10 K cycles at 3.0 A g^-1) compared to those of bulk g-C₃N₄.

Metal-Organic Framework-Derived ZnSe- and Co0.85Se-Filled Porous Nitrogen-Doped Carbon Nanocubes Interconnected by Reduced Graphene Oxide for Sodium-Ion Battery Anodes

Transition-metal selenides have been considered as one of the most promising anode materials for sodium-ion batteries (SIBs) due to their high theoretical capacity and excellent rate performance. However, rapid capacity decay and poor cycling stability limit their practical application as the anode for SIBs. Carbon coating is one of the most effective ways to solve the above problems, but the thickness and uniformity of the coating layer are difficult to control. Herein, we successfully synthesize metal-organic framework (MOF)-derived porous N-doped carbon nanocubes homogeneously filled with ZnSe and Co_0.85Se and interconnected by reduced graphene oxide (ZCS@NC@rGO). ZCS@NC@rGO with more active sites and the synergistic effect of the ZnSe and Co_0.85Se heterojunction can enhance the sodium storage performance. The porous carbon nanocubes effectively prevent the agglomeration of active particles, and the rGO acting as a carbon network can significantly buffer the inevitable volume changes. At the same time, carbon nanocubes and the rGO are interconnecting to form a conductive network to accelerate electron transfer. Based on the aforementioned advantages, the ZCS@NC@rGO electrode shows an excellent sodium storage performance. Our investigation opens up a new horizon for the rational design of transition-metal selenide anodes for SIBs with a unique structure.