Resumos
Computational Hydrogen Electrode Utilizing DFT for Comprehensive Evaluation of Hydrogen Evolution Reactions in Diamond-Like Functionalized Nanosheets
Bruno Ipaves e Pedro Alves da Silva Autreto
Resumo:
Since the groundbreaking discovery of graphene in 2004, extensive research has been conducted on two-dimensional (2D) materials, making them highly attractive for energy
storage and catalytic conversion applications. The physical properties of 2D materials exhibit
significant variations depending on the synthesis and functionalization methods employed,
and the underlying factors responsible for these diverse properties remain a topic of ongoing
investigation. Therefore, it is of utmost importance to explore and gain a comprehensive
understanding of the properties of functionalized 2D structures. In our previous studies [1, 2],
we have already examined the structural, thermodynamic, dynamic, elastic, and electronic
properties of diamond-like graphene and diamond-like silicene nanosheets functionalized
with different types of atoms. Notably, we focused on the diamond-like silicene nanosheet
functionalized with aluminum atoms, which has shown great promise as a potential candidate
for alkali metal ion batteries, particularly sodium and potassium ion batteries [3].
Additionally, our recent findings indicate that these diamond-like functionalized nanosheets
hold significant potential for facilitating efficient hydrogen evolution reactions (HER).
Herein, our objective is to demonstrate the utilization of density functional theory (DFT) in
investigating battery materials and computational hydrogen electrode approach, enabling the
estimation of crucial properties such as open-circuit voltage, theoretical capacity, and HER
activity
Computational Methods for Investigation of Transport Properties
Caique Campos de Oliveira e Pedro Alves da Silva Autreto
Resumo:
The advancement of computational methods has sparked a revolution in materials
science. Both classical and quantum descriptions of materials have empowered theorists to
gain insights into phenomena and scales that are difficult to access experimentally. Density
Functional Theory (DFT) [1] is a well-established methodology for computational studies of
the structural and electronic properties of materials across various applications, such as
nanoelectronics, topological insulators, and superconductivity. Transport properties, including
electronic and thermal conductivities, play a significant role in many of these applications.
These variables are closely linked to the thermoelectric performance of the material, which is
useful for energy harvesting applications. To explore these quantities further, DFT results can
be combined with Boltzmann’s semiclassical transport theory, allowing for the study of
thermoelectric properties in a straightforward manner. In this work, we provide a concise
introduction to the Boltzmann semiclassical transport theory, specifically within the time
relaxation approximation, as implemented in the BoltzTraP code [2]. By utilizing
Fourier-transformed interpolated band structure energies, obtained from well-established DFT
implementations (e.g., Quantum ESPRESSO [3]), one can solve analytical functions to
determine transport parameters, including the Seebeck coefficient, electrical conductivity, and
thermal conductivity. Finally, we present a practical example by investigating the effects of
hydrogenation on the transport of a two-dimensional carbon allotrope.
Nanoporous Biphenylene as Catalyst for Electrochemical Reactions
Lanna E. B. Lucchetti, Caique Campos, Pedro S. Autreto, James M. Almeida
Resumo:
Electrochemical processes have been in the spotlight on the recent years, as we gather efforts
worldwide to pave the way towards greener energy generation. Besides, different
electrochemical reactions can also address urgent environmental problems. Among these
processes are the hydrogen evolution reaction, the oxygen oxidation reaction, and the water
oxidation reaction. For most applications, the main obstacle for the large-scale
implementation of these processes is the need for cheap, efficient, and earth-abundant
catalysts as cost-effective alternatives to the benchmark scarce noble-metal materials. In this
sense, metal-free carbon-based catalysts have drawn considerable attention and especially
graphene-based nanostructures have been extensively investigated. In this work, we
investigate a novel material – carbon biphenylene (BPC), a sp² carbon allotrope with intrinsic
in-plane nanoporous structure. The main objective of this work is to investigate if different
metal single-atom dopings can improve BPC catalytic activity. The hydrogen evolution and
the oxidation reaction have been selected as catalytic activity descriptors, and DFT
calculations of these different reaction pathways have been performed with the Quantum
Espresso package. Our results indicate that metal doping is an interesting strategy to enhance
the catalytic activity, optimizing the intermediate species adsorption free-energy.