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Extensive studies have been carried out on two-dimensional (2D) metal carbides (MCs) as prospective nominees for alkali-metal ion batteries (AMIBs). These materials have attracted interest because of their substantial specific surface area, enabling them to accommodate a large quantity of metal ions along with their excellent diffusivity. However, the high metal content in these materials results in strong Coulomb’s repulsive interactions with Li/Na/K ions, leading to a low storage capacity. To tackle this challenge, we have adjusted the carbon composition in 2D WC4to enhance its storage capacity and mitigate the repulsive forces between W and Li/Na/K ions. Our computational analysis has revealed that the WC4monolayer maintains dynamic and thermal stability, with a robust cohesive energy that supports its experimental synthesis. The WC4monolayer, as an anode material, exhibits high electronic conductivity and diffusivity and rapid ion transfer rate, as verified by low activation energy barriers of 0.55 eV for Li-ion batteries (LIBs), 0.084 eV for Na-ion batteries (SIBs), and 0.081 eV for K-ion batteries (PIBs), which facilitate robust charging and discharging processes. Additionally, the average voltages calculated for Li-, Na-, and K-ion batteries are 0.65, 0.46, and 0.42 V, respectively. Consequently, the WC4monolayer demonstrates impressive Li, Na, and K storage capacities, reaching 577, 462, and 462 mA h g–1, respectively, for maximum loading. These results demonstrate that 2D WC4as a promising anode material for alkali-ion batteries.

Hydrogen is a significantly advantageous clean and sustainable energy carrier over other energy sources. Therefore, hydrogen production using water-splitting technology is a promising strategy as a clean source of energy. In this work, we computationally explored the effect of different surface functionalization on the structural, electronic, and optical properties of Cr2CT2MXenes (T = F, Cl, H, and OH) for water-splitting applications. The pure functionalization resulted in antiferromagnetic (AFM) spin-unpolarized MXenes, while the mixed functionalization induced asymmetric AFM semiconductor formation. A tunable band gap size is achievable under different functionalization of Cr2CT2MXenes. Most of the functionalized Cr2CT2MXenes display band gaps in the visible range with band edge alignment appropriate for water-splitting reactions. In addition, an indirect band gap characteristic is observed for some of the functionalized MXenes, which is beneficial for the spatial charge pair separation and migration. The results presented herein enrich our understanding of the optoelectronic properties of potential functionalized MXenes as photocatalysts for water-splitting reactions and inspire experimentalists to find the suitable MXene candidate for such applications.

Considerable interest is directed toward next-generation electrochemical energy storage systems due to their massive applications in powered electronic devices. Silicon is an anode material for metal-ion batteries due to its high storage capacity. However, poor electronic conductivity and volume alteration during the intercalation and deintercalation process impede its performance as an anode. To overwhelm these issues, herein, two-dimensional (2D) lightweight SiN3is proposed to combine the properties of silicon and nitrogen. Density functional theory (DFT) examines the mechanism of SiN3monolayer as an anode with exceptional efficacy for (Li+, Na+)-based batteries. SiN3monolayer is found to be thermally, mechanically, and dynamically stable. The maximum theoretical capacity of 1146 mA h g−1for (Li+, Na+)-based batteries is obtained. The calculated values of the diffusion barrier are as small as 0.025 eV for Li and 0.034 eV for Na, which help in the rapid diffusion of Li+and Na+on the SiN3monolayer. Also, the obtained average open circuit voltages of 0.43 V for Li3SiN3and 0.47 V for Na3SiN3meet the commercial design. These findings indicate that the newly reported SiN3monolayer is an attractive anode material for (Li+, Na+)-based batteries. These outcomes provide a way for experimentalists to explore SiN3-based anode materials for battery applications.

We demonstrate quantum mechanically how to resolve enantiomers from an oriented racemic mixture taking advantage of photodissociation. Our approach employs a femtosecond ultraviolet (UV) laser pulse with specific linear polarization achieving selective photodissociation of one enantiomer from a mixture of L and R enantiomers. As a result, the selected enantiomer is destroyed in the electronically excited state while the opposite enantiomer is left intact in the ground state. As an example we use H2POSD which presents axial chirality. A UV pulse excites the lowest singlet excited state which has nσ* character and is, therefore, strongly repulsive along the P–S bond. The model simulations are performed using wavepackets which propagate on two dimensional potential energy surfaces, calculated along the chirality and dissociation reaction coordinates using the CASSCF level of theory.