Strain-induced stabilization of Al functionalization in graphene oxide nanosheet for enhanced NH3 storage

Abstract

Strain effects on the stabilization of Al dopant atom in graphene oxide (GO) nanosheet as well as its implications for NH 3 storage have been investigated using firstprinciples calculations. The high binding energy of Al ad-atom on GO is found to be a false indicator of its stability. The structural instability clearly contradicts the otherwise high stability indicated by the energetics of Al's binding to GO, stressing the need to assess the stability both from energetic and structural perspectives. Tensile strain effectively stabilizes the Al ad-atom on the GO nanosheet by strengthening the C-O bonds through an enhanced electronic charge transfer from C to O atoms. Interestingly, the strength of the C-O bonds is found to be the correct index for Al's stability. The trend for the variation of binding energy with strain is at odds with the systematic analysis of electronic structure based on bond lengths and atomic charges. At an optimal level of strain, the NH 3 storage capacity of Al-decorated GO is found to reach its maximum, where each Al ad-atom is able to bind up to 6 NH 3 molecules to itself with binding energies in the range of 0.2-1.1 eV. In contrast, the unstrained Al-doped GO is not found to bind even a single NH 3 molecule.

Conversion of CO2and C2H6to Propanoic Acid on an Iridium-Modified Graphene Oxide Surface: Quantum-Chemical Investigation

“…An iterative conjugate-gradient (CG) algorithm was performed for a self-consistent calculation of the electronic ground state. The reason for using GGA is that it had been widely applied to simulate and optimize the graphene and graphene oxide system in the literature. − In addition, it had been also recommended to calculate noble metal (Ir, Au, Pt, etc.) containing systems by the PW91 exchange-correlation function (such as IrO 2 (110) surface and Au 10 /graphene oxide).…”

“…The single-layered graphite oxide (GO) can serve as an alternative support for noble-metal clusters; the synthesis can be controlled by the coverage of oxygen on the graphene oxide, of which the popularity has been increasing because of its superior electronic properties and improved catalytic activities. , The metal atom, such as Mg, Al, Ti, and Fe, on graphene oxide is reported to have a large adsorption energy for gas capture and significant catalytic properties. − Graphene oxide materials promote the oxidation of CO to avoid significantly poisoning the catalyst. , …”

Boron-Decorated Graphitic Carbon Nitride (g-C3N4): An Efficient Sensor for H2S, SO2, and NH3 Capture

“…Most researchers are now conducting various theoretical works , on novel and inexpensive sensor materials with high sensitivity and selectivity to minimize their expenses in experimental testing. Among these sensing materials, carbon-based substances with unique nanostructures play important roles in gas capturing due to their high surface area and light weight. − These latter materials offer a wide range of experimental and theoretical applications in the domain of energy storage , and gas sensing. − However, they offer a weak detection ability toward hazardous gases (e.g., H 2 S, SO 2 , and NH 3 ). Constraint by inherent weak interactions within their nanostructures, researchers are compelled to find different strategies (e.g., functionalize their surfaces with transition metals or even create defects within them) to enhance the detection capacity of these carbon-based materials.…”

Magnetoresistance of AlGaN/GaN High Electron Mobility Transistors on Silicon

“…AlGaN/GaN heterojunctions can be utilized in high electron mobility transistors (HEMT) for power electronic applications, high frequency devices and space applications. The investigated structure is epitaxially grown on Si-wafers, which are much cheaper than conventional substrates like SiC or sapphire [1]. However, a sophisticated growth recipe is required for high quality GaN layers on Si because of the large lattice mismatch.…”