Density functional theory (DFT) computations were performed to investigate the electronic properties and Li storage capability of Ti(3)C(2), one representative MXene (M represents transition metals, and X is either C or/and N) material, and its fluorinated and hydroxylated derivatives. The Ti(3)C(2) monolayer acts as a magnetic metal, while its derived Ti(3)C(2)F(2) and Ti(3)C(2)(OH)(2) in their stable conformations are semiconductors with small band gaps. Li adsorption forms a strong Coulomb interaction with Ti(3)C(2)-based hosts but well preserves its structural integrity. The bare Ti(3)C(2) monolayer exhibits a low barrier for Li diffusion and high Li storage capacity (up to Ti(3)C(2)Li(2) stoichiometry). The surface functionalization of F and OH blocks Li transport and decreases Li storage capacity, which should be avoided in experiments. The exceptional properties, including good electronic conductivity, fast Li diffusion, low operating voltage, and high theoretical Li storage capacity, make Ti(3)C(2) MXene a promising anode material for Li ion batteries.

The 1T phase of transition metal dichalcogenides (TMDs) has been demonstrated in recent experiments to display catalytic activity for hydrogen evolution reaction (HER), but the catalytic mechanism has not been elucidated so far. Herein, using 1T MoS 2 as the prototypical TMD material, we studied the HER activity on its basal plane from periodic density functional theory (DFT) calculations. Compared to the non-reactive basal plane of 2H phase MoS 2 , the catalytic activity of the basal plane of 1T phase MoS 2 mainly arises from its affinity for binding H at the surface S sites. Using the binding free energy (∆G H ) of H as the descriptor, we found that the optimum evolution of H 2 will proceed at surface H coverage of 12.5% ~ 25%. Within this coverage, we examined the reaction energy and kinetic activation barrier for the three elementary steps of the HER process. The Volmer step was found to be facile, while the subsequent Heyrovsky reaction is kinetically more favorable than the Tafel reaction. Our results suggest that at low overpotential, HER can take place readily on the basal plane of 1T MoS 2 via the Volmer-Heyrovsky mechanism. We further screened the dopants for the HER activity and found that substitutional doping of the Mo atom by metals such as Mn, Cr, Cu, Ni, and Fe can make 1T MoS 2 a better HER catalyst.

The bottom-up assembly of nanoparticles into diverse ordered solids is a challenge because it requires nanoparticles, which are often quasi-spherical, to have interaction anisotropy akin to atoms and molecules. Typically, anisotropy has been introduced by changing the shape of the inorganic nanoparticle core. Here, we present the design, self-assembly, optical properties, and total structural determination of Ag29(BDT)12(TPP)4, an atomically precise tetravalent nanocluster (NC) (BDT, 1,3-benzenedithiol; TPP, triphenylphosphine). It features four unique tetrahedrally symmetrical binding surface sites facilitated by the supramolecular assembly of 12 BDT (wide footprint bidentate thiols) in the ligand shell. When each of these sites was selectively functionalized by a single phosphine ligand, particle stability, synthetic yield, and the propensity to self-assemble into macroscopic crystals increased. The solid crystallized NCs have a substantially narrowed optical band gap compared to that of the solution state, suggesting strong interparticle electronic coupling occurs in the solid state.

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In this review, we discuss the most recent progress on graphene-related nanomaterials, including doped graphene and derived graphene nanoribbons, graphene oxide, graphane, fluorographene, graphyne, graphdiyne, and porous graphene, from both experimental and theoretical perspectives, and emphasize tuning their stability, electronic and magnetic properties by chemical functionalization.