Room-temperature stabilization of metastable β-NiMoO is achieved through urea-assisted hydrothermal synthesis technique. Structural and morphological studies provided significant insights for the metastable phase. Furthermore, detailed electrochemical investigations showcased its activity toward energy storage and conversion, yielding intriguing results. Comparison with the stable polymorph, α-NiMoO, has also been borne out to support the enhanced electrochemical activities of the as-obtained β-NiMoO. A specific capacitance of ∼4188 F g (at a current density of 5 A g) has been observed showing its exceptional faradic capacitance. We qualitatively and extensively demonstrate through the analysis of density of states (DOS) obtained from first-principles calculations that, enhanced DOS near top of the valence band and empty 4d orbital of Mo near Fermi level make β-NiMoO better energy storage and conversion material compared to α-NiMoO. Likewise, from the oxygen evolution reaction experiment, it is found that the state of art current density of 10 mA cm is achieved at overpotential of 300 mV, which is much lower than that of IrO/C. First-principles calculations also confirm a lower overpotential of 350 mV for β-NiMoO

Here, we report the facile synthesis of NiCoO (NCO) and NiCoO-Pd (NCO-Pd) nanosheets by the electrodeposition method. We observed enhanced glucose-sensing performance of NCO-Pd nanosheets as compared to bare NCO nanosheets. The sensitivity of the pure NCO nanosheets is 27.5 μA μM cm, whereas NCO-Pd nanosheets exhibit sensitivity of 40.03 μA μM cm. Density functional theory simulations have been performed to qualitatively support our experimental observations by investigating the interactions and charge-transfer mechanism of glucose on NiCoO and Pd-doped NiCoO through demonstration of partial density of states and charge density distributions. The presence of occupied and unoccupied density of states near the Fermi level implies that both Ni and Co ions in NiCoO can act as communicating media to transfer the charge from glucose by participating in the redox reactions. The higher binding energy of glucose and more charge transfer from glucose to Pd-doped NiCoO compared with bare NiCoO infer that Pd-doped NiCoO possesses superior charge-transfer kinetics, which supports the higher glucose-sensing performance.

For the first time, we predict through density functional theory that a single Zr atom attached on graphene surface can adsorb maximum of 9 H2 molecules with average binding energy of 0.34 eV and average desorption temperature of 433 K leading to a wt % of 11, higher than the DoE’s requirement of 6.5 wt %.The dependency of desorption temperature (T D ) of H2 molecule with the magnetic moment (μ) of the system was exclusively studied by formulating the empirical relation T D = T 0 + aμ b (with T 0 = 399 K, a = 302.38 J–1 T K and b = 0.5). For a system with a large magnetic moment, the charge transfer to the hydrogen molecule is higher, leading to higher desorption temperature (may be higher than prescribed limit for hydrogen storage by DoE). As the magnetic moment reduces, T D comes into the desired window for fuel cell applications. It can be inferred from this study that controlling the magnetic character of the system through doping may be an effective way to bring T D in to the desired window. We qualitatively and extensively demonstrate through the analysis of the partial density of states and Bader charge transfer the interaction mechanism of Zr on graphene surface and hydrogen storage capability of Zr decorated graphene. As we have used GGA exchange correlations (LDA over binds the system), checked the stability through ab initio MD simulations, computed the diffusion barrier for avoiding metal–metal clustering, and predicted that the hydrogen wt % of the system (11 wt %) comes higher than the DoE’s requirement (6.5 wt %) with desorption temperature (433 K) and is very much suitable for fuel cell applications, we strongly believe that Zr-doped graphene can be tailored as a high capacity hydrogen storage device.

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Here, we report the controlled hydrothermal synthesis and tuning of the pure monoclinic phase of WO3 and WO3-Ag nanostructures. Comparative electrochemical nonenzymatic glucose sensing properties of WO3 and WO3-Ag were investigated by cyclic voltammetry and chronoamperometric tests. We observed enhanced glucose sensing performance of WO3-Ag porous spheres as compared to bare WO3 nanoslabs. The sensitivity of the pure WO3 nanoslabs is 11.1 μA μM−1 cm−2 whereas WO3-Ag porous spheres exhibit sensitivity of 23.3 μA μM−1 cm−2. The WO3-Ag porous spheres exhibited a good linear range (5–375 μM) with excellent anti-interference property. Our experimental observations are qualitatively supported by density functional theory simulations through investigation of bonding and charge transfer mechanism of glucose on WO3 and Ag doped WO3. As the binding energy of glucose is more on the Ag doped WO3 (100) surface compared to the bare WO3 (100) surface and the Ag doped WO3 (100) surface becomes more conducting due to enhancement of density of states near the Fermi level, we can infer that Ag doped WO3 exhibits a better charge transfer media compared to bare WO3 resulting in enhanced glucose sensitivity in consistency with our experimental data.

Hydrothermally obtained MoO 3 /reduced graphene oxide (RGO) hybrid registered a specific capacitance of 724 F g -1 at 1 A g -1 , superior to the supercapacitor performance obtained from similar hybrid structures. Density functional theory (DFT) simulations further corroborated our claim in terms of both enhanced quantum capacitance and relevant insight from the electronic density of states (DOS) for MoO 3 /RGO. Maximum capacitance is achieved for 12 wt % of RGO and then it reduces as observed in the experiment. The appearance of additional density of states from the C p z orbital in the band gap region near the Fermi level on introduction of RGO in MoO 3 is responsible for the enhanced capacitance in MoO 3 /RGO.

Insertion of lead and lead telluride in Bi2Te3 leads to a change in the thermal conductivity, frequency shift, and the broadening of phonon modes.

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