Presently, great attention is focused on the search for promising anode materials due to the rapid development of electronic products. In this study, by means of density functional calculations, we have predicted that a bilayer covalent triazine framework (CTF) may be a promising anode material for rechargeable lithium-ion batteries (LIBs). Our calculations reveal that lithium atoms can be preferably inserted into the interlayer spacing of the bilayer CTF. The calculations indicate charge transfer from Li atoms to the bilayer CTF. After lithium adsorption, the bilayer CTF undergoes a transition from a semiconductor to a metal, ensuring good electrical conductivity of the electrode material. Furthermore, the bilayer CTF can achieve a high theoretical specific capacity of 925.99 mAh/g and a moderately low diffusion barrier of 0.65 eV. Our calculated average open-circuit voltages (OCVs) lie in the range of 1.58–0.51 V, which are in between those of some typical anode materials. All of these calculations suggest that the bilayer CTF can be used as a potential anode material for LIBs.

The electrocatalytic nitrogen reduction reaction (NRR) has garnered significant attention from the scientific community because it is considered a simple, green, and sustainable method for ammonia (NH3) production. However, the lack of suitable electrocatalysts with high activity and selectivity prevents the large-scale production of NH3 through electrocatalytic N2 fixation. To search potential electrocatalysts for NRR, herein, using density functional theory (DFT)-based calculations, we investigated the suitability of a molybdenum atom-doped salphen-based covalent organic framework (Mo-salphenCOF) as an electrocatalyst toward NRR. Our findings suggest that Mo-salphenCOF is both thermodynamically and electrochemically stable. Mo-salphenCOF displays excellent electrocatalytic activity toward NRR with a very low limiting potential of −0.33 V vs a reverse hydrogen electrode (RHE) through the preferred distal mechanism. Mo-salphenCOF displays a low kinetic barrier of 0.42 eV at 0 V vs RHE for the least thermodynamically favored step along the most favored distal pathway. As far as the catalytic selectivity of Mo-salphenCOF is concerned, it can moderately suppress the competing hydrogen evolution reaction (HER) both at zero and NRR operating potential (−0.33 V vs RHE) with a substantial theoretical faradic efficiency (FE) of 41%. Moreover, the inclusion of an implicit solvation model showed positive results for both the activity and selectivity of our proposed electrocatalyst (Mo-salphenCOF) toward NRR. Therefore, the high stability, excellent catalytic activity, and substantial catalytic selectivity of Mo-salphenCOF make it a potential candidate as an electrocatalyst toward NRR.

Electrocatalytic water spliting is the most attractive route for hydrogen production, but the development of nonprecious, stable, and high-performance catalysts for hydrogen evolution reaction (HER) to replace the scarce platinum group metal-based electrocatalysts is still a challenging task for the scientific community. In this work, within the framework of density functional theory computations, we have predicted that a silicon and phosphorus co-doped bipyridine-linked covalent triazine framework, followed by substitution of bipyridine hydrogens at the P-site with fluorine atoms, may be a potential catalyst for HER. Our predicted model system (SiPF-Bpy-CTF) exhibits a very low band gap (7 meV), which may exhibit facile charge transfer kinetics during HER. Using the Gibbs free energy for the adsorption of atomic hydrogen ( ) as the key descriptor, we have found that our proposed model system (SiPF-Bpy-CTF) exhibits superior HER catalytic activity, with its being close to the ideal value (0 eV).

Because of the low cost and plentiful resources of sodium as compared to lithium, sodium-ion batteries (SIBs) are becoming promising alternatives to lithium-ion batteries for large-scale electrochemical energy storage applications. However, the non-availability of appropriate anode materials restricts the use of SIBs. We have herein made an attempt to investigate the suitability of a triformylphloroglucinol (TP) and triazine triamine (TT)-based bilayer organic framework (TPTT) as an anode material for SIBs using density functional theory-based computations. Our study reveals that the bilayer TPTT is a direct band gap semiconductor with a band gap value of 2.64 eV. The triazine framework undergoes a transition from semiconductor to metal after adsorption of sodium at the most favorable carbonyl oxygen (CO) site, thus ensuring good electrical conductivity. The good electrical conductivity, moderate diffusion barrier (0.56 eV), high theoretical specific capacity (855 mA h/g), average voltage (0.43 V) in the range required for suitable anode materials (0.1–1.00 V), and structural flexibility compel us to infer that the bilayer TPTT may be a potential candidate as an anode material for SIBs.

One of the potential strategies to solve renewable energy shortage is to design low-cost efficient photocatalysts for water splitting to aid hydrogen and oxygen evolution reactions (HER and OER). Two-dimensional (2D) materials like MXenes and transition metal dichalcogenides (TMDs) have caught special attention owing to their unique optical, electrical, and mechanical properties, but come with issues like photocorrosion and poor charge separation. Bilayer vdW heterojunctions of suitable constitutive monolayers are coming up as a potential solution to these hazards, accredited to their tunable band gap and efficient charge separation. In this paper, we have investigated the possibility of Ti 2 CO 2 −WX 2 (X = S, Se, Te) vdW heterostructures to perform as Z-scheme photocatalysts by employing firstprinciple density functional calculations, and thereby, the Ti 2 CO−WSe 2 heterostructure has emerged as the most promising material for Z-scheme photocatalysis. Further, excited-state dynamics simulation reveals that the timescales of electron transfer and hole transfer are greater (1.13 and 1.22 ps, respectively) than the maximum time limit of the photogenerated electron−hole recombination (1.0 ps) owing to the weaker non-adiabatic coupling and electron−phonon coupling. This affirms the fact that photogenerated electrons and holes with greater redox ability are preserved to drive the photocatalytic pathway. In addition to that, the free energy calculations associated with the HER and OER processes entail that the processes occur spontaneously on the surface of the heterostructure without any co-catalyst. This establishes the Ti 2 CO−WSe 2 heterostructure as a potential mediator-free direct Z-scheme photocatalyst for overall water splitting.