TY  - JOUR
AU  - Stavrić, Srđan
AU  - Chesnyak, Valeria
AU  - del Puppo, Simone
AU  - Panighel, Mirco
AU  - Comelli, Giovanni
AU  - Africh, Cristina
AU  - Šljivančanin, Željko
AU  - Peressi, Maria
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/11833
AB  - The role of moiré graphene superstructures in favoring confined adsorption of different metal atoms is an intriguing problem not yet completely solved. Graphene (G) grown on Ni(100) forms a striped moiré pattern of valleys, where G approaches the nickel substrate and interacts with it rather strongly, and ridges, where G stays far away from the substrate and acts almost free-standing. Combining density functional theory (DFT) calculations and scanning-tunneling microscopy (STM) measurements, we show that this peculiar moiré constitutes a regular nanostructured template on a 2D support, confining in 1D trails single metal atoms and few atoms clusters. DFT calculations show that the confinement is selective and highly dependent on the atomic species, with some species preferring to adsorb on ridges and the other showing preference for valleys. Co and Au adsorbates, for instance, have opposite behavior, as predicted by DFT and observed by STM. The origin of such disparate behavior is traced back to the electrostatic interaction between the charged adsorbate and the nickel surface. Moreover, the selectivity is not restricted to the adsorption process only, but persists as adsorbate starts its diffusion, resulting in unidirectional mass transport on a continuous 2D support. These findings hold great promise for exploiting tailored nanostructured templates in a wide range of potential applications involving mass transport along element-specific routes.
T2  - Carbon
T1  - 1D selective confinement and diffusion of metal atoms on graphene
VL  - 215
SP  - 118486
DO  - 10.1016/j.carbon.2023.118486
ER  - 

@article{
author = "Stavrić, Srđan and Chesnyak, Valeria and del Puppo, Simone and Panighel, Mirco and Comelli, Giovanni and Africh, Cristina and Šljivančanin, Željko and Peressi, Maria",
year = "2023",
abstract = "The role of moiré graphene superstructures in favoring confined adsorption of different metal atoms is an intriguing problem not yet completely solved. Graphene (G) grown on Ni(100) forms a striped moiré pattern of valleys, where G approaches the nickel substrate and interacts with it rather strongly, and ridges, where G stays far away from the substrate and acts almost free-standing. Combining density functional theory (DFT) calculations and scanning-tunneling microscopy (STM) measurements, we show that this peculiar moiré constitutes a regular nanostructured template on a 2D support, confining in 1D trails single metal atoms and few atoms clusters. DFT calculations show that the confinement is selective and highly dependent on the atomic species, with some species preferring to adsorb on ridges and the other showing preference for valleys. Co and Au adsorbates, for instance, have opposite behavior, as predicted by DFT and observed by STM. The origin of such disparate behavior is traced back to the electrostatic interaction between the charged adsorbate and the nickel surface. Moreover, the selectivity is not restricted to the adsorption process only, but persists as adsorbate starts its diffusion, resulting in unidirectional mass transport on a continuous 2D support. These findings hold great promise for exploiting tailored nanostructured templates in a wide range of potential applications involving mass transport along element-specific routes.",
journal = "Carbon",
title = "1D selective confinement and diffusion of metal atoms on graphene",
volume = "215",
pages = "118486",
doi = "10.1016/j.carbon.2023.118486"
}

Stavrić, S., Chesnyak, V., del Puppo, S., Panighel, M., Comelli, G., Africh, C., Šljivančanin, Ž.,& Peressi, M.. (2023). 1D selective confinement and diffusion of metal atoms on graphene. in Carbon, 215, 118486.
https://doi.org/10.1016/j.carbon.2023.118486

Stavrić S, Chesnyak V, del Puppo S, Panighel M, Comelli G, Africh C, Šljivančanin Ž, Peressi M. 1D selective confinement and diffusion of metal atoms on graphene. in Carbon. 2023;215:118486.
doi:10.1016/j.carbon.2023.118486 .

Stavrić, Srđan, Chesnyak, Valeria, del Puppo, Simone, Panighel, Mirco, Comelli, Giovanni, Africh, Cristina, Šljivančanin, Željko, Peressi, Maria, "1D selective confinement and diffusion of metal atoms on graphene" in Carbon, 215 (2023):118486,
https://doi.org/10.1016/j.carbon.2023.118486 . .

TY  - JOUR
AU  - Chesnyak, Valeria
AU  - Stavrić, Srđan
AU  - Panighel, Mirco
AU  - Comelli, Giovanni
AU  - Peressi, Maria
AU  - Africh, Cristina
PY  - 2022
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/10208
AB  - The influence on the growth of cobalt (Co)-based nanostructures of a surface carbide (Ni2C) layer formed at the Ni(100) surface is revealed via complementary scanning tunneling microscopy (STM) measurements and first-principles calculations. On clean Ni(100) below 200 °C in the sub-monolayer regime, Co forms randomly distributed two-dimensional (2D) islands, while on Ni2C it grows in the direction perpendicular to the surface as well, thus forming two-atomic-layers high islands. We present a simple yet powerful model that explains the different Co growth modes for the two surfaces. A jagged step decoration, not visible on stepped Ni(100), is present on Ni2C. This contrasting behavior on Ni2C is explained by the sharp differences in the mobility of Co atoms for the two cases. By increasing the temperature, Co dissolution is activated with almost no remaining Co at 250 °C on Ni(100) and Co islands still visible on the Ni2C surface up to 300 °C. The higher thermal stability of Co above the Ni2C surface is rationalized by ab initio calculations, which also suggest the existence of a vacancy-assisted mechanism for Co dissolution in Ni(100). The methodology presented in this paper, combining systematically STM measurements with first-principles calculations and computational modelling, opens the way to controlled engineering of bimetallic surfaces with tailored properties.
T2  - Nanoscale
T1  - Carbide coating on nickel to enhance the stability of supported metal nanoclusters
VL  - 14
IS  - 9
SP  - 3589
EP  - 3598
DO  - 10.1039/D1NR06485A
ER  - 

@article{
author = "Chesnyak, Valeria and Stavrić, Srđan and Panighel, Mirco and Comelli, Giovanni and Peressi, Maria and Africh, Cristina",
year = "2022",
abstract = "The influence on the growth of cobalt (Co)-based nanostructures of a surface carbide (Ni2C) layer formed at the Ni(100) surface is revealed via complementary scanning tunneling microscopy (STM) measurements and first-principles calculations. On clean Ni(100) below 200 °C in the sub-monolayer regime, Co forms randomly distributed two-dimensional (2D) islands, while on Ni2C it grows in the direction perpendicular to the surface as well, thus forming two-atomic-layers high islands. We present a simple yet powerful model that explains the different Co growth modes for the two surfaces. A jagged step decoration, not visible on stepped Ni(100), is present on Ni2C. This contrasting behavior on Ni2C is explained by the sharp differences in the mobility of Co atoms for the two cases. By increasing the temperature, Co dissolution is activated with almost no remaining Co at 250 °C on Ni(100) and Co islands still visible on the Ni2C surface up to 300 °C. The higher thermal stability of Co above the Ni2C surface is rationalized by ab initio calculations, which also suggest the existence of a vacancy-assisted mechanism for Co dissolution in Ni(100). The methodology presented in this paper, combining systematically STM measurements with first-principles calculations and computational modelling, opens the way to controlled engineering of bimetallic surfaces with tailored properties.",
journal = "Nanoscale",
title = "Carbide coating on nickel to enhance the stability of supported metal nanoclusters",
volume = "14",
number = "9",
pages = "3589-3598",
doi = "10.1039/D1NR06485A"
}

Chesnyak, V., Stavrić, S., Panighel, M., Comelli, G., Peressi, M.,& Africh, C.. (2022). Carbide coating on nickel to enhance the stability of supported metal nanoclusters. in Nanoscale, 14(9), 3589-3598.
https://doi.org/10.1039/D1NR06485A

Chesnyak V, Stavrić S, Panighel M, Comelli G, Peressi M, Africh C. Carbide coating on nickel to enhance the stability of supported metal nanoclusters. in Nanoscale. 2022;14(9):3589-3598.
doi:10.1039/D1NR06485A .

Chesnyak, Valeria, Stavrić, Srđan, Panighel, Mirco, Comelli, Giovanni, Peressi, Maria, Africh, Cristina, "Carbide coating on nickel to enhance the stability of supported metal nanoclusters" in Nanoscale, 14, no. 9 (2022):3589-3598,
https://doi.org/10.1039/D1NR06485A . .

TY  - JOUR
AU  - Stavrić, Srđan
AU  - Chesnyak, Valeria
AU  - Panighel, Mirco
AU  - Comelli, Giovanni
AU  - Africh, Cristina
AU  - Peressi, Maria
PY  - 2022
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/10704
AB  - Transition metal atoms are commonly used in catalysis and photo-catalysis, but their potential reactivity reduces with aggregation and alloying. We investigate in particular whether Cobalt adatoms float on Ni surfaces or dissolve into the metal. Density functional theory calculations have been performed in order to evaluate the stability of different Cobalt adsorption configurations on Nickel surfaces, mainly at (100) terraces and steps, and the relevant energy barriers for diffusion on terraces and across steps, segregation and dissolution into the substrate. The simulations have been compared with variable temperature scanning tunneling microscopy and low energy electron diffraction. The results show that the Cobalt adatoms and small aggregates are unstable with respect to the formation of Co-Ni alloys, but the presence of a carbide monolayer on Ni surface improve their stability. © 2022 Societa Italiana di Fisica. All rights reserved.
T2  - Il Nuovo Cimento C
T1  - Cobalt on nickel surfaces and the role of carbide on its stability
VL  - 45
IS  - 6
DO  - 10.1393/ncc/i2022-22177-5
ER  - 

@article{
author = "Stavrić, Srđan and Chesnyak, Valeria and Panighel, Mirco and Comelli, Giovanni and Africh, Cristina and Peressi, Maria",
year = "2022",
abstract = "Transition metal atoms are commonly used in catalysis and photo-catalysis, but their potential reactivity reduces with aggregation and alloying. We investigate in particular whether Cobalt adatoms float on Ni surfaces or dissolve into the metal. Density functional theory calculations have been performed in order to evaluate the stability of different Cobalt adsorption configurations on Nickel surfaces, mainly at (100) terraces and steps, and the relevant energy barriers for diffusion on terraces and across steps, segregation and dissolution into the substrate. The simulations have been compared with variable temperature scanning tunneling microscopy and low energy electron diffraction. The results show that the Cobalt adatoms and small aggregates are unstable with respect to the formation of Co-Ni alloys, but the presence of a carbide monolayer on Ni surface improve their stability. © 2022 Societa Italiana di Fisica. All rights reserved.",
journal = "Il Nuovo Cimento C",
title = "Cobalt on nickel surfaces and the role of carbide on its stability",
volume = "45",
number = "6",
doi = "10.1393/ncc/i2022-22177-5"
}

Stavrić, S., Chesnyak, V., Panighel, M., Comelli, G., Africh, C.,& Peressi, M.. (2022). Cobalt on nickel surfaces and the role of carbide on its stability. in Il Nuovo Cimento C, 45(6).
https://doi.org/10.1393/ncc/i2022-22177-5

Stavrić S, Chesnyak V, Panighel M, Comelli G, Africh C, Peressi M. Cobalt on nickel surfaces and the role of carbide on its stability. in Il Nuovo Cimento C. 2022;45(6).
doi:10.1393/ncc/i2022-22177-5 .

Stavrić, Srđan, Chesnyak, Valeria, Panighel, Mirco, Comelli, Giovanni, Africh, Cristina, Peressi, Maria, "Cobalt on nickel surfaces and the role of carbide on its stability" in Il Nuovo Cimento C, 45, no. 6 (2022),
https://doi.org/10.1393/ncc/i2022-22177-5 . .