RESUMEN
Ti-MXene allows a range of possibilities to tune their compositional stoichiometry due to their electronic and electrochemical properties. Other than conventionally explored Ti-MXene, there have been ample opportunities for the non-Ti-based MXenes, especially the emerging Mo-based MXenes. Mo-MXenes are established to be remarkable with optoelectronic and electrochemical properties, tuned energy, catalysis, and sensing applications. In this timely review, we systematically discuss the various organized synthesis procedures, associated experimental tunning parameters, physiochemical properties, structural evaluation, stability challenges, key findings, and a wide range of applications of emerging Mo-MXene over Ti-MXenes. We also critically examined the precise control of Mo-MXenes to cater to advanced applications by comprehensively evaluating the summary of recent studies using artificial intelligence and machine learning tools. The critical future perspectives, significant challenges, and possible outlooks for successfully developing and using Mo-MXenes for various practical applications are highlighted.
RESUMEN
In this study, we have prepared cobalt selenide (CoSe2) due to its useful aspects from a catalysis point of view such as abundant active sites from Se edges, and significant stability in alkaline conditions. CoSe2, however, has yet to prove its functionality, so we doped palladium oxide (PdO) onto CoSe2 nanostructures using ultraviolet (UV) light, resulting in an efficient and stable water oxidation composite. The crystal arrays, morphology, and chemical composition of the surface were studied using a variety of characterization techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FTIR) spectroscopy. It was also demonstrated that the composite systems were heterogeneous in their morphology, undergoing a shift in their diffraction patterns, suffering from a variety of metal oxidation states and surface defects. The water oxidation was verified by a low overpotential of 260 mV at a current density of 20 mA cm-2 with a Tafel Slope value of 57 mV dec-1. The presence of multi metal oxidation states, rich surface edges of Se and favorable charge transport played a leading role towards water oxidation with a low energy demand. Furthermore, 48 h of durability is associated with the composite system. With the use of PdO and CoSe2, new, low efficiency, simple electrocatalysts for water catalysis have been developed, enabling the development of practical energy conversion and storage systems. This is an excellent alternative approach for fostering growth in the field.
RESUMEN
The geometries, electronic properties, and chemical bonding of (VH2)n (n=10-30) nanoclusters are systematically investigated by a combination of artificial bee colony optimization with density functional theory calculations. Structure analysis indicates that the structures of (VH2)n nanoclusters tend to be a disorder, where the hydrogen atoms prefer to occupy the hollow sites among different V atoms, binding three V atoms to form the HV3 moieties. The bond length suggests that the average V-V bond lengths are about 2.60 Å, and the average V-H bond lengths are near 1.86 Å, which close to the experimental values of 2.77 Å and 1.79 Å for the V-V and V-H of bulk vanadium hydride, respectively. Interestingly, the coordination numbers of V-H fluctuate around 5.50 in the nanoclusters, and the corresponding value of H-V is estimated at 3.00. Moreover, the electronic properties and chemical bonding analyses indicate that d orbitals of V atoms and s orbitals of H atoms have a relatively large overlap to form sigma bonds. Specifically, the σ molecular orbital of H2 can donate electronic density to the d orbital of V atom, exhibiting the Kubas interaction in V24H48 and V29H58 nanoclusters. Kubas interaction results in a longer bond between the hydrogen molecule and the V atom.
