scholarly journals Covalent Functionalization of Nickel Phosphide Nanocrystals with Aryl-Diazonium Salts

2021 ◽  
Author(s):  
Ian Murphy ◽  
Peter Rice ◽  
Madison Monahan ◽  
Leo Zasada ◽  
Elisa Miller ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Photoelectron Spectroscopy ◽  
Density Functional ◽  
Binding Energies ◽  
Diazonium Salts ◽  
Surface Functional Group ◽  
Covalent Functionalization ◽  
Substitution Pattern ◽  
Core Electron ◽  
Functional Theory

Covalent functionalization of Ni2P nanocrystals was demonstrated using aryl-diazonium salts. Spontaneous adsorption of aryl functional groups was observed, with surface coverages ranging from 20-96% depending on the native reactivity of the salt as determined by the aryl substitution pattern. Increased coverage was possible for low reactivity species using a sacrificial reductant. Functionalization was confirmed using thermogravimetric analysis, FTIR and X-ray photoelectron spectroscopy. The structure and energetics of this nanocrystal electrocatalyst system, as a function of ligand coverage, was explored with density functional theory calculations. The Hammett parameter of the surface functional group was found to linearly correlate with the change in Ni and P core-electron binding energies and the nanocrystal’s experimentally and computationally determined work-function. The electrocatalytic activity and stability of the functionalized nanocrystals for hydrogen evolution were also improved when compared to the unfunctionalized material, but a simple trend based on electrostatics was not evident. We used density functional theory to understand this discrepancy and found that H adsorption energies on the covalently functionalized Ni2P also do not follow the electrostatic trend and are predictive descriptors of the experimental results.

scholarly journals Covalent Functionalization of Nickel Phosphide Nanocrystals with Aryl-Diazonium Salts

2021 ◽  
Author(s):  
Ian Murphy ◽  
Peter Rice ◽  
Madison Monahan ◽  
Leo Zasada ◽  
Elisa Miller ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Photoelectron Spectroscopy ◽  
Density Functional ◽  
Binding Energies ◽  
Diazonium Salts ◽  
Surface Functional Group ◽  
Covalent Functionalization ◽  
Substitution Pattern ◽  
Core Electron ◽  
Functional Theory

Covalent functionalization of Ni2P nanocrystals was demonstrated using aryl-diazonium salts. Spontaneous adsorption of aryl functional groups was observed, with surface coverages ranging from 20-96% depending on the native reactivity of the salt as determined by the aryl substitution pattern. Increased coverage was possible for low reactivity species using a sacrificial reductant. Functionalization was confirmed using thermogravimetric analysis, FTIR and X-ray photoelectron spectroscopy. The structure and energetics of this nanocrystal electrocatalyst system, as a function of ligand coverage, was explored with density functional theory calculations. The Hammett parameter of the surface functional group was found to linearly correlate with the change in Ni and P core-electron binding energies and the nanocrystal’s experimentally and computationally determined work-function. The electrocatalytic activity and stability of the functionalized nanocrystals for hydrogen evolution were also improved when compared to the unfunctionalized material, but a simple trend based on electrostatics was not evident. Density functional theory was used to understand this discrepancy, revealing that H adsorption energies on the covalently functionalized Ni2P also do not follow the electrostatic trend and are predictive descriptors of the experimental results.

Density functional theory study of allopurinol

2013 ◽  
Vol 91 (7) ◽  
pp. 637-641 ◽  
Author(s):  
Delano P. Chong
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Binding Energies ◽  
Dipole Polarizability ◽  
Equilibrium Geometry ◽  
Core Electron ◽  
Functional Theory ◽  
Valence Electrons ◽  
Vertical Ionization Energies ◽  
Electron Binding Energies

Allopurinol vapour is studied with density functional theory. Using the best method from past experience for each property, we predict the equilibrium geometry, vibrational spectrum, dipole moment, average dipole polarizability, UV absorption spectrum, vertical ionization energies of valence electrons, and core-electron binding energies.

Density-functional calculation of core-electron binding energies of glycine conformers

1996 ◽  
Vol 74 (6) ◽  
pp. 1005-1007 ◽  
Author(s):  
Delano P. Chong
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Binding Energies ◽  
Basis Set ◽  
Stable Conformer ◽  
Absolute Deviation ◽  
Core Electron ◽  
Functional Theory ◽  
Electron Binding Energies ◽  
Electron Binding

Our recent procedure of computing accurate core-electron binding energies (CEBEs) with density-functional theory is applied to glycine conformers in this work. The procedure uses the unrestricted generalized transition-state model and a combined functional of Becke's 1988 exchange with Perdew's 1986 correlation. When a large basis set such as Dunning's correlation-consistent polarized valence quadruple zeta set is used, the average absolute deviation from experiment for the CEBEs of the most stable conformer of glycine is only 0.2 eV, compared with 18 eV for Koopmans' theorem. Key words: core-electron binding energies, density-functional theory, glycine.

Density functional theory study of the vertical ionization energies of the valence and core electrons of cyclopentadiene, pyrrole, furan, and thiophene

2011 ◽  
Vol 89 (12) ◽  
pp. 1477-1488 ◽  
Author(s):  
Delano P. Chong
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Binding Energies ◽  
Test Cases ◽  
Absolute Deviation ◽  
Core Electron ◽  
Functional Theory ◽  
Ionization Energies ◽  
Benchmark Database ◽  
Vertical Ionization Energies

The procedure abbreviated as ΔPBE0(SAOP)/et-pVQZ, based on density functional theory, was developed recently for the calculation of vertical ionization energies of the valence electrons of organic and other small molecules and succeeded in giving results with an average absolute deviation of 0.21 eV from experiment for a collection of 115 reliable test cases of nonperhalo molecules. The objective of this work is to add a number of test cases to the benchmark database. We chose the set of molecules cyclo-C4H4X, with X = CH2, NH, O, and S, previously studied by many workers both experimentally and theoretically. The results show that the ΔPBE0(SAOP)/et-pVQZ procedure is not only as good as ab initio methods such as SAC-CI, OVGF, and ADC(3) in performance, but also handles inner valence ionized cations more efficiently. Although the core-electron binding energies of the titled molecules have not been as well investigated theoretically, we apply the methods we developed in recent years to calculate the binding energies of C1s, N1s, O1s, S1s, and S2p, which compare well with available experimental data.

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