TY  - JOUR
AU  - Chesnyak, Valeria
AU  - Stavrić, Srđan
AU  - Panighel, Mirco
AU  - Povoledo, Daniele
AU  - del Puppo, Simone
AU  - Peressi, Maria
AU  - Comelli, Giovanni
AU  - Africh, Cristina
PY  - 2024
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/13282
AB  - To improve reactivity and achieve a higher material efficiency, catalysts are often used in the form of clusters with nanometer dimensions, down to single atoms. Since the corresponding properties are highly structure-dependent, a suitable support is thus required to ensure cluster stability during operating conditions. Herein, an efficient method to stabilize cobalt nanoclusters on graphene grown on nickel substrates, exploiting the anchoring effect of nickel atoms incorporated in the carbon network is presented. The anchored nanoclusters are studied by in situ variable temperature scanning tunneling microscopy at different temperatures and upon gas exposure. Cluster stability upon annealing up to 200 °C and upon CO exposure at least up to 1 × 10−6 mbar CO partial pressure is demonstrated. Moreover, the dimensions of the cobalt nanoclusters remain surprisingly small (<3 nm diameter) with a narrow size distribution. Density functional theory calculations demonstrate that the interplay between the low diffusion barrier on graphene on nickel and the strong anchoring effect of the nickel atoms leads to the increased stability and size selectivity of these clusters. This anchoring technique is expected to be applicable also to other cases, with clear advantages for transition metals that are usually difficult to stabilize.
T2  - Small Structures
T1  - Exceptionally Stable Cobalt Nanoclusters on Functionalized Graphene
SP  - 2400055
DO  - 10.1002/sstr.202400055
ER  - 

@article{
author = "Chesnyak, Valeria and Stavrić, Srđan and Panighel, Mirco and Povoledo, Daniele and del Puppo, Simone and Peressi, Maria and Comelli, Giovanni and Africh, Cristina",
year = "2024",
abstract = "To improve reactivity and achieve a higher material efficiency, catalysts are often used in the form of clusters with nanometer dimensions, down to single atoms. Since the corresponding properties are highly structure-dependent, a suitable support is thus required to ensure cluster stability during operating conditions. Herein, an efficient method to stabilize cobalt nanoclusters on graphene grown on nickel substrates, exploiting the anchoring effect of nickel atoms incorporated in the carbon network is presented. The anchored nanoclusters are studied by in situ variable temperature scanning tunneling microscopy at different temperatures and upon gas exposure. Cluster stability upon annealing up to 200 °C and upon CO exposure at least up to 1 × 10−6 mbar CO partial pressure is demonstrated. Moreover, the dimensions of the cobalt nanoclusters remain surprisingly small (<3 nm diameter) with a narrow size distribution. Density functional theory calculations demonstrate that the interplay between the low diffusion barrier on graphene on nickel and the strong anchoring effect of the nickel atoms leads to the increased stability and size selectivity of these clusters. This anchoring technique is expected to be applicable also to other cases, with clear advantages for transition metals that are usually difficult to stabilize.",
journal = "Small Structures",
title = "Exceptionally Stable Cobalt Nanoclusters on Functionalized Graphene",
pages = "2400055",
doi = "10.1002/sstr.202400055"
}

Chesnyak, V., Stavrić, S., Panighel, M., Povoledo, D., del Puppo, S., Peressi, M., Comelli, G.,& Africh, C.. (2024). Exceptionally Stable Cobalt Nanoclusters on Functionalized Graphene. in Small Structures, 2400055.
https://doi.org/10.1002/sstr.202400055

Chesnyak V, Stavrić S, Panighel M, Povoledo D, del Puppo S, Peressi M, Comelli G, Africh C. Exceptionally Stable Cobalt Nanoclusters on Functionalized Graphene. in Small Structures. 2024;:2400055.
doi:10.1002/sstr.202400055 .

Chesnyak, Valeria, Stavrić, Srđan, Panighel, Mirco, Povoledo, Daniele, del Puppo, Simone, Peressi, Maria, Comelli, Giovanni, Africh, Cristina, "Exceptionally Stable Cobalt Nanoclusters on Functionalized Graphene" in Small Structures (2024):2400055,
https://doi.org/10.1002/sstr.202400055 . .

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 . .