Oxygen evolution reaction: a perspective on a decade of atomic scale simulations

Multiple strategies to overcome the intrinsic limitations of the oxygen evolution reaction (OER) have been proposed by numerous research groups. Despite the substantial efforts, the driving force required for water oxidation is largely making the reaction inefficient. In the present work, we collected published studies involving DFT calculations for the OER, with the purpose to understand why the progress made so far, for lowering the overpotential of the reaction, is relatively small. The data revealed that the universal scaling relationship between HO* and HOO* intermediates is still present and robust, despite the variety in methods and structures used for calculating the binding energies of the intermediates. On the other hand, the data did not show a clear trend line regarding the O* binding. Our analysis suggested that trends in doped semiconducting oxides behave very differently from those in other oxides. This points towards a computational challenge in describing doped oxides in a realistic manner. We propose a way to overcome these computational challenges, which can be applied to simulations corresponding to doped semiconductors in general

Experimental and Calculated Vibrational Circular Dichroism Spectra of an Iminosugar Molecule: (2R, 3R, 4R) 1,4-dideoxy-1,4-imino-D-arabinitol Hydrochloride

The first vibrational circular dichroism (VCD) measurement of a biologically important iminosugar, (2R, 3R, 4R) 1,4-dideoxy-1,4-imino-D-arabinito

Role of the Band Gap for the Interaction Energy of Coadsorbed Fragments

Understanding the interaction between adsorbants and metal surfaces has led to descriptors for bindings and catalysis which have a major impact on the design of metal catalysts. On semiconductor oxides, these understandings are still lacking. We show an important element in understanding binding on semiconductors. We propose here a correlation between the cooperative interaction energy, i.e., the energy difference between the adsorption energies of coadsorbed electron donor–acceptor pair and isolated fragments and the band gap of the clean oxide surface. We demonstrate this effect for a number of oxides and donor–acceptor pairs and explain it with the shift in the Fermi level before and after the adsorption. The conclusion is that the adsorption of acceptor–donor pairs is considerably more favorable compared to unpaired fragments, and this energy difference is approximately equal to the value of the band gap. The implications of this understanding in relation to the improvement and discovery of novel catalysts on the band gap oxides are also discussed

First principle studies of oxygen reduction reaction on N doped graphene: Impact of N concentration, position and co-adsorbate effect

Density Functional Theory calculations were performed on N doped graphene sheet to investigate the trends for adsorption energy variation of oxygen reduction reaction intermediates (HOO*, O*, HO*) when the N concentration increases from 0N (0%) to 1N (33%), to 2N (67%) and to 3N (100%) around the C active site. The impact of the distance between the doping N atoms and the C active site is also studied. Last, the impact of additionally co-adsorbed HO*/O* intermediates was probed. For all the studied systems the magnitudes with which varies the adsorption energies are shaped by the HO*/HOO* capability of accommodating less charge than O* (i.e according to octet rule 1e− vs. 2e−). When N concentration increases, adsorption energy of O* increases with a much higher magnitude than that of HO*/HOO* (i.e with 5 eV vs. 2.7 eV, when going from 0N to 3N). In the presence of the O* co-adsorbate, adsorption energy of intermediates on the investigated active site decrease with a much higher magnitude than when 1HO* is present as co-adsorbate (≈2 eV vs. 1 eV). The theoretical overpotential trends are evaluated using ΔGHO*-ΔGO* descriptor and are found to be significantly influenced by all these environmental changes around the active site. By applying the water stabilization effects, the activity trends remain the same as when it is not taken into account. These results reveal aspects of ORR activity variations that take place when N is clustering on graphene sheets, structures that can be possible as a function of synthesis procedures that could lead to unevenly distribution of dopants in the matrix

First principle studies of oxygen reduction reaction on N doped graphene: Impact of N concentration, position and co-adsorbate effect

Density Functional Theory calculations were performed on N doped graphene sheet to investigate the trends for adsorption energy variation of oxygen reduction reaction intermediates (HOO*, O*, HO*) when the N concentration increases from 0N (0%) to 1N (33%), to 2N (67%) and to 3N (100%) around the C active site. The impact of the distance between the doping N atoms and the C active site is also studied. Last, the impact of additionally co-adsorbed HO*/O* intermediates was probed. For all the studied systems the magnitudes with which varies the adsorption energies are shaped by the HO*/HOO* capability of accommodating less charge than O* (i.e according to octet rule 1e− vs. 2e−). When N concentration increases, adsorption energy of O* increases with a much higher magnitude than that of HO*/HOO* (i.e with 5 eV vs. 2.7 eV, when going from 0N to 3N). In the presence of the O* co-adsorbate, adsorption energy of intermediates on the investigated active site decrease with a much higher magnitude than when 1HO* is present as co-adsorbate (≈2 eV vs. 1 eV). The theoretical overpotential trends are evaluated using ΔGHO*-ΔGO* descriptor and are found to be significantly influenced by all these environmental changes around the active site. By applying the water stabilization effects, the activity trends remain the same as when it is not taken into account. These results reveal aspects of ORR activity variations that take place when N is clustering on graphene sheets, structures that can be possible as a function of synthesis procedures that could lead to unevenly distribution of dopants in the matrix

Supporting data - Effects of the cooperative interaction on the diffusion of hydrogen on MgO(100)

This dataset is the supporting data for the manuscript <i>"Effects of the cooperative interaction on the diffusion of hydrogen on MgO(100)"</i>, I.E. Castelli, Stefan G. Soriga, Isabela C. Man, J. Chem. Phys. 49, 034704 (2018). In the manuscript, we have investigated the role of pre-adsorbed fragments on H diffusion on MgO(100).<br><br>The data set contains all the relaxed structures and Nudged Elastic Bands (NEB) calculations in xyz and traj (Atomic Simulation Environment - ASE) format. Each structure can be visualized with the command:<br>ase gui filename.traj (or .xyz)<br>The NEB calculations with:<br>ase gui -n -1 *initial.traj *im?.traj *final.traj<br>and then select NEB from Tools. An example of the plot of a NEB calculation is the figure included here.<br><br>The scripts used to run and analyze the calculations are included in the archive. <br><br>A README file with more information about the data set and links have been provided.<br><br>The ASE code can be found here: https://wiki.fysik.dtu.dk/ase/<br><br