Catalytic performance of graphene quantum dot supported manganese phthalocyanine for efficient oxygen reduction: density functional theory approach

2019 ◽  
Vol 43 (1) ◽  
pp. 348-355 ◽  
Author(s):  
Nguyet N. T. Pham ◽  
Jong S. Park ◽  
Hee-Tak Kim ◽  
Hyoung-Juhn Kim ◽  
Young-A Son ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Free Energy ◽  
Quantum Dot ◽  
Oxygen Reduction ◽  
Density Functional ◽  
Catalytic Performance ◽  
Theory Approach ◽  
Functional Theory ◽  
Graphene Quantum Dot ◽  
Orr Activity

The thermodynamic free-energy diagrams predict that MnPc/GQD is more active toward ORR than the isolated MnPc, clearly highlighting the effect of the GQD matrix on ORR activity from a thermodynamic perspective.

scholarly journals A density functional theory study of the oxygen reduction reaction on the (111) and (100) surfaces of cobalt(II) oxide

2019 ◽  
Vol 44 (2) ◽  
pp. 122-131
Author(s):  
Bangchang Qin ◽  
Yang Tian ◽  
Pengxiang Zhang ◽  
Zuoyin Yang ◽  
Guoxin Zhang ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Free Energy ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Gibbs Free Energy ◽  
Density Functional ◽  
Rational Design ◽  
Reduction Reaction ◽  
Functional Theory ◽  
Associative Mechanism

Density functional theory calculations were employed to investigate the electrochemical oxygen reduction reaction on the (111) and (100) surfaces of cobalt(II) oxide. Different mechanisms were applied to evaluate the oxygen reduction reaction performance of cobalt(II) oxide structures in terms of the Gibbs free energy and density of states. A variety of intermediate structures based on associative and dissociative mechanisms were constructed and optimized. As a result, we estimated the catalytic activity by calculating the free energy of the intermediates and constructing free energy diagrams, which suggested that the oxygen reduction reaction Gibbs free energy on cobalt(II) oxide (111) and (100) surfaces based on the associative mechanism is smaller than that based on the dissociative mechanism, demonstrating that the associative mechanism should be more likely to be the oxygen reduction reaction pathway. Moreover, the theoretical oxygen reduction reaction activity on the cobalt(II) oxide (111) surface was found to be higher than that on the cobalt(II) oxide (100) surface. These results shed light on the rational design of high-performance cobalt(II) oxide oxygen reduction reaction catalysts.

scholarly journals Tuning the optoelectronic properties of hematite with rhodium doping for photoelectrochemical water splitting using density functional theory approach

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Abdur Rauf ◽  
Muhammad Adil ◽  
Shabeer Ahmad Mian ◽  
Gul Rahman ◽  
Ejaz Ahmed ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Optical Properties ◽  
Optical Absorption ◽  
Water Splitting ◽  
Density Functional ◽  
Formation Energy ◽  
Visible Region ◽  
Photoelectrochemical Water Splitting ◽  
Theory Approach ◽  
Functional Theory

AbstractHematite (Fe2O3) is one of the best candidates for photoelectrochemical water splitting due to its abundance and suitable bandgap. However, its efficiency is mostly impeded due to the intrinsically low conductivity and poor light absorption. In this study, we targeted this intrinsic behavior to investigate the thermodynamic stability, photoconductivity and optical properties of rhodium doped hematite using density functional theory. The calculated formation energy of pristine and rhodium doped hematite was − 4.47 eV and − 5.34 eV respectively, suggesting that the doped material is thermodynamically more stable. The DFT results established that the bandgap of doped hematite narrowed down to the lower edge (1.61 eV) in the visible region which enhanced the optical absorption and photoconductivity of the material. Moreover, doped hematite has the ability to absorb a broad spectrum (250–800) nm. The enhanced optical absorption boosted the photocurrent and incident photon to current efficiency. The calculated results also showed that the incorporation of rhodium in hematite induced a redshift in optical properties.

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