We use density functional theory calculations to study a group of 2D materials known as MXenes toward the electrochemical nitrogen reduction reaction (NRR) to ammonia. So far, all computational studies have only considered the NRR chemistry on unfunctionalized (bare) MXenes. In this study, we investigate a total of 65 bare and functionalized MXenes. We establish free energy diagrams for the NRR on the basal planes of 55 different M 2 XT x MXenes (M = Ti, V, Zr, Nb, Mo, Ta, W; X = C, N) to span a large variety of possible chemistries. Energy trends with respect to the metal as well as nonmetal constituent of the MXenes are established for both bare and functionalized MXenes. We determine the limiting potentials and find that either the formation of NH 3 from *NH 2 or the formation of *N 2 H is the potential limiting reaction step for bare and functionalized MXenes, respectively. We find several Mo-, W-, and V-based MXenes (Mo 2 C, Mo 2 N, W 2 N, W 2 NH 2 , and V 2 N) to have suitable theoretical overpotentials for the NRR. Importantly, calculated Pourbaix stability diagrams combined with selectivity analysis, however, reveal that all bare MXenes are not stable under relevant NRR operating conditions. The only functionalized MXene with the three minimum required properties (i) having a low theoretical overpotential, (ii) being stable under NRR conditions, and (iii) having selectivity toward NRR rather than the parasitic HER is W 2 CH 2 , which is a H-terminated MXene. Finally, on the basis of our findings, we explore other routes for improving the NRR chemistry by studying 10 additional MXenes with the chemical formula M 3 X 2 T x and MXenes with other functional groups (T x = S, F, Cl). This opens up a larger variety and tunability of MXenes to be considered for the NRR.

Hydrodeoxygenation (HDO) of m-cresol to produce toluene over carbon-supported Pt and Pt-WO x catalysts was studied. In stark contrast to Pt/C that exhibits only modest selectivity and low stability for this reaction, Pt-WO x /C was found to be unusually active and selective to toluene with greater than 94% selectivity to this product while exhibiting little to no deactivation under a wide range of reaction conditions. Reactivity studies in combination with density functional theory (DFT) calculations for the adsorption and reaction of m-cresol on structurally optimized WO x -decorated Pt(111) structures indicate that the HDO reaction on Pt-WO x /C proceeds via a direct hydrogenolysis of the C–O bond in m-cresol adsorbed on oxygen vacancy (or redox) sites on WO x species. The DFT results also indicate that Pt helps stabilize the WO x film while facilitating oxygen vacancy formation.

This study has been conducted with the objective of investigating the effects of zinc oxide nanoparticles on the structural and electrical properties of polyvinyl alcohol films. The fabricated nanocomposites were characterised by Fourier transform infrared spectroscopy, UV-visible (vis) spectra, X-ray diffraction and SEM techniques. UV-vis spectra showed that the addition of ZnO nanoparticles did not affect the absorbance in the visible region of nanocomposites. The SEM image showed that ZnO nanoparticles were homogeneously dispersed throughout the entire film's polymeric matrix. The dielectric properties were found to be strongly dependent on frequency and nanofiller content. AC conductivity s ac of polyvinyl alcohol/ZnO nanocomposites increased with increasing frequency. The dissipation factor tan d also increased with nanoparticle addition and decreased with frequency. At low nanofiller concentrations, nanocomposites exhibited low dielectric values at higher frequency, thus behaving like a lossless material, making them suitable for utilisation in microwave applications.

The objective of this study was to investigate the effects of CuO nanoparticles on the structural, thermal and electrical properties of polyvinyl alcohol (PVA) thin films. The thin films were prepared by a solution casting technique with different weight percentages viz., 0.5, 1.0, 1.5 and 2.0 wt% of CuO nanoparticles in PVA matrix. The fabricated nanocomposite thin films were structurally characterised by Fourier transform infrared spectroscopy and X-ray diffraction, while differential scanning calorimetry indicated the effect of CuO nanoparticles on thermal properties of PVA. The surface morphology of the films was determined by scanning electron microscopy technique. Dielectric properties were analysed using high frequency LCR metre and were found to be dependent on frequency and CuO concentration. Dielectric constant decreased with increase in both frequency and CuO concentration. Dielectric loss increased with frequency increase and decreased with increase in CuO concentration. AC conductivity increased with increase in frequency. PVA-2.0 wt% CuO nanocomposite was found to possess desirable properties such as low dielectric constant and low dielectric loss which makes it a desirable material for use in microelectronics industry.

This study has been conducted to investigate the effect of incorporating CuO nanoparticles inside PVA matrix with the aim of enhancing the mechanical properties of PVA for reinforcement purposes. Films were prepared by solution intercalation technique with 0.5, 1.0, 1.5 and 2.0 wt% CuO nanofiller content taking neat PVA as the reference for the study. Structural characterisations of the prepared nanocomposite films were carried out by FTIR, SEM and XRD techniques. Various mechanical parameters such as tensile strength, elastic modulus, flexural strength and toughness were investigated and significant enhancement in the properties of polyvinyl alcohol films containing CuO nanofillers was observed. Elastic modulus and toughness showed a linear relation with respect to nanofiller concentration at low wt%, whereas at higher wt% of CuO, the nature was observed to be non-linear. PVA-2.0 wt% CuO nanocomposite showed the highest values of flexural strength, toughness and tensile strength among all the fabricated nanocomposite films.