Elementary kinetics of nitrogen electroreduction to ammonia on late transition metals

2019 ◽  
Vol 9 (1) ◽  
pp. 174-181 ◽  
Author(s):  
Gholamreza Rostamikia ◽  
Sharad Maheshwari ◽  
Michael J. Janik

Nitrogen reduction reaction barriers calculated by density functional theory quantify NRR activity and selectivity challenges.

2021 ◽  
Author(s):  
Xin Zhang ◽  
Liu Leo Liu

We report herein the synthesis, characterization, and coordination chemistry of a free N-aluminylene, namely a carbazolylaluminylene 2b. This species is prepared via a reduction reaction of the corresponding carbazolyl aluminium diiodide. The coordination behavior of 2b towards transition metal centers (W, Cr) is shown to afford a series of novel aluminylene complexes 3-6 with diverse coordination modes. We demonstrate that the Al center in 2b can behave as: 1. a σ-donating and doubly π-accepting ligand; 2. a σ-donating, σ-accepting and π-accepting ligand; and 3. a σ-donating and doubly σ-accepting ligand. Additionally, we show ligand exchange at the aluminylene center providing access to the modulation of electronic properties of transition metals without changing the coordinated atoms. Investigations of 2b with IDippCuCl (IDipp = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) show an unprecedented aluminylene-alumanyl transformation leading to a rare terminal Cu-alumanyl complex 8. The electronic structures of such complexes and the mechanism of the aluminylene-alumanyl transformation are investigated through density functional theory (DFT) calculations.


2020 ◽  
Author(s):  
Marti Lopez ◽  
Francesc Vines ◽  
Michael Nolan ◽  
Frances Illas

Previous work has shown that doping the TiC(001) surface with early transition metals significantly affects CO<sub>2</sub> adsorption and activation which opens a possible way to control this interesting chemistry. In this work we explore other possibilities which include non-transition metals elements (Mg, Ca, Sr, Al, Ga, In, Si, Sn) as well as late transition metals (Pd, Pt, Rh, Ir) and lanthanides (La, Ce) often used in catalysis. Using periodic slab models with large supercells and state-of-the-art density functional theory (DFT) based calculations, we show that, in all the studied cases, CO<sub>2</sub> appears as bent and, hence, activated. However, the effect is especially pronounced for dopants with large ionic crystal radii. These can increase desorption temperature by up to 230K, almost twice the value predicted when early transition metals are used as dopants. However, a detailed analysis of the results shows that the main effect does not come from electronic structure perturbations but from the distortion that the dopant generates into the surface atomic structure. A simple descriptor is proposed that would allow predicting the effect of the dopant on the CO<sub>2</sub> adsorption energy in transition metal carbide surfaces without requiring DFT calculations.


2016 ◽  
Vol 18 (4) ◽  
pp. 2949-2958 ◽  
Author(s):  
Bikram Kumar Das ◽  
Dipayan Sen ◽  
K. K. Chattopadhyay

Dispersive force corrected density functional theory is used to map the oxygen reduction reaction (ORR) kinetics of six kinds of graphyne (Gy) and graphdiyne (Gdy) systems (namely αGy, βGy, γGy, δGy, 6,6,12Gy, RGy and Gdy) with substitutional boron (B) atom doping.


2020 ◽  
Author(s):  
Marti Lopez ◽  
Francesc Vines ◽  
Michael Nolan ◽  
Frances Illas

Previous work has shown that doping the TiC(001) surface with early transition metals significantly affects CO<sub>2</sub> adsorption and activation which opens a possible way to control this interesting chemistry. In this work we explore other possibilities which include non-transition metals elements (Mg, Ca, Sr, Al, Ga, In, Si, Sn) as well as late transition metals (Pd, Pt, Rh, Ir) and lanthanides (La, Ce) often used in catalysis. Using periodic slab models with large supercells and state-of-the-art density functional theory (DFT) based calculations, we show that, in all the studied cases, CO<sub>2</sub> appears as bent and, hence, activated. However, the effect is especially pronounced for dopants with large ionic crystal radii. These can increase desorption temperature by up to 230K, almost twice the value predicted when early transition metals are used as dopants. However, a detailed analysis of the results shows that the main effect does not come from electronic structure perturbations but from the distortion that the dopant generates into the surface atomic structure. A simple descriptor is proposed that would allow predicting the effect of the dopant on the CO<sub>2</sub> adsorption energy in transition metal carbide surfaces without requiring DFT calculations.


RSC Advances ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 3174-3182
Author(s):  
Siwei Yang ◽  
Chaoyu Zhao ◽  
Ruxin Qu ◽  
Yaxuan Cheng ◽  
Huiling Liu ◽  
...  

In this study, a novel type oxygen reduction reaction (ORR) electrocatalyst is explored using density functional theory (DFT); the catalyst consists of transition metal M and heteroatom N4 co-doped in vacancy fullerene (M–N4–C64, M = Fe, Co, and Ni).


Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2560
Author(s):  
Jianwen Meng ◽  
Yong Pan ◽  
Fan Yang ◽  
Yanjun Wang ◽  
Zhongyu Zheng ◽  
...  

The thermal stability and decomposition kinetics analysis of 1-alkyl-2,3-dimethylimidazole nitrate ionic liquids with different alkyl chains (ethyl, butyl, hexyl, octyl and decyl) were investigated by using isothermal and nonisothermal thermogravimetric analysis combined with thermoanalytical kinetics calculations (Kissinger, Friedman and Flynn-Wall-Ozawa) and density functional theory (DFT) calculations. Isothermal experiments were performed in a nitrogen atmosphere at 240, 250, 260 and 270 °C. In addition, the nonisothermal experiments were carried out in nitrogen and air atmospheres from 30 to 600 °C with heating rates of 5, 10, 15, 20 and 25 °C/min. The results of two heating modes, three activation energy calculations and density functional theory calculations consistently showed that the thermal stability of 1-alkyl-2,3-dimethylimidazolium nitrate ionic liquids decreases with the increasing length of the alkyl chain of the substituent on the cation, and then the thermal hazard increases. This study could provide some guidance for the safety design and use of imidazolium nitrate ionic liquids for engineering.


Author(s):  
Yuwen Cheng ◽  
Jisheng Mo ◽  
Yongtao Li ◽  
Yan Song ◽  
Yumin Zhang

Recently, transition metal borides (MBenes, analogous to MXenes) have been attracted interest due to their potential applications in energy conversion and storage. In this work, we performed density functional theory...


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