Density Functional Theory for Electrocatalysis

Abstract

With the increase in energy demand and worldwide natural environment crises, it is imperative to develop green and sustainable energy systems to produce clean fuels and chemicals, which can replace fossil fuels and reduce carbon dioxide emissions. [1][2][3] A promising strategy is to develop advanced electrochemical technologies that can convert some common molecules (e.g., water, carbon dioxide, and nitrogen) into high-value chemical products (e.g., hydrogen, hydrocarbons, oxygenates, ammonia, and carbonates). [4][5][6][7] The important energy-related electrocatalytic reactions, including hydrogen evolution reaction (HER), oxygen evolution reaction (OER), oxygen reduction reaction (ORR), nitrogen reduction reaction (NRR), carbon dioxide reduction reaction (CO 2 RR), are the key conversion routes. In the complex processes for the electrocatalytic reactions, an efficient, highly selective, and stable electrocatalyst plays a pivotal role in speeding up the reaction kinetics and decreasing the overpotential, [5,8,9] which can enhance the sustainable energy conversion efficiency. Over the past few decades, tremendous progresses have been made in the establishment of electrocatalysts preparation and fundamental catalytic mechanisms. [6,7,[9][10][11][12][13][14][15][16][17][18] Nevertheless, those breakthroughs still stay at the stage of experimental synthesis and lack of indepth understanding of fundamental principles of the active site on the catalyst surface and catalytic reactions mechanisms, which seriously limits the development of efficient catalysts. Researchers are full of enthusiasm about preparation of advanced catalysts with ideal properties, expecting to establish the composition-structure-function relationships. Density functional theory (DFT) calculations are based on quantum mechanics, which can calculate the electronic structure of the whole catalytic system. It is probably the most powerful computational approach to investigate the structure-activity relationships of electrocatalysts at atomic level. With the rapid advances of computer technology, DFT calculations have created tremendous opportunities in shedding light on the electrocatalytic mechanisms and predicting promising catalysts. [19,20] Identification of the active sites and understanding of the reaction mechanisms are the two key aspects for the study of electrocatalytic reactions. [21] For the former, the experimental approach for identifying active sites is indirect by prepared specified catalysts and establishing definite correlations between catalytic performances and controllable factors. [22,23] Actually, many intermediate states of electrocatalytic

Coordination environments tune the activity of oxygen catalysis on single atom catalysts: A computational study

“…The interactions between ion cores and valence electrons were depicted by the projector √ 3 augmented wave (PAW) basis set with a cutoff energy of 500 eV [40]. Meanwhile, we used the Perdew-Burke-Ernzerhof (PBE) functional within the generalized gradient approximation (GGA) to describe the exchange-correlation potential [41,42], which was based on the comparison of *OH adsorption energy between the functional of PBE and revised Perdew-Burke-Ernzerhof (RPBE) in Table S2 in the Electronic Supplementary Material (ESM) according to the analysis of Luo et al and Liao et al [43,44]. All the TM-N 3 -C and TM-N 4 -C structural models were built based on the monolayer graphene plane model with the supercell of 5 × 3 × 1 (12.30 Å × 12.78 Å × 15.00 Å).…”

Dehydro-Sulfurization Utilizing Doubly-Charged Negative Ions of Molybdenum Disulfide (MoS2), Graphene-Flake (GR-28), Armchair Carbon Nanotube (CNT 6,6), and Fullerene (C-60) as Catalysts for Depollution, Natural Resource Mining, and the Chemical Functiona

“…These calculations support the application of the short-lived ion creation fundamental mechanism to multistep chemical reactions. The transition state barriers presented here suggest efficacy for reaction barrier optimization or "chemical tuning" for future depollution and elemental S acquisition applications [18,24,26].…”

“…Hence, the oxygen is removed from the sulfur dioxide due to bond breakage to form 3 molar diatomic sulfurs and 4 molar waters in the final product of step 2. The addition of doubly-charged negative ions to the spherical, cylindrical, and planar nanoscale catalysts function as a "chemical tuning" agent for each step of the dehydro-sulfurization reaction [26,27]. Moreover, the varying of the catalysts with each step of the redox reaction mimics the biocatalytic mechanism of sucrose conversion to organic honey through the flow of 2e-electrons that similarly cause bond breakage and bond reformation as shown in figures 8-10.…”

Revealing the Multi‐Electron Reaction Mechanism of Na3V2O2(PO4)2F Towards Improved Lithium Storage

“…Combined with the above results, the theoretical ion insertion/extraction mechanism of NVOPF/G and the ions locations were also executed by density functional theory (DFT) calculations. [26] The detail information of the simulated structures, including the initial and final structural models of the obtained phases (Figure S7), cell parameters (Table S3) and Li-Li distances in the optimized models (Table S4) are provided in the Supporting Information. Considering the experimental and theoretical analysis, the crystal structure illustrations are presented in Figure 3d-h.…”