TY  - JOUR
AU  - Smiljanić, Milutin Lj.
AU  - Bele, Marjan
AU  - Moriau, Léonard Jean
AU  - Vélez Santa, John Fredy
AU  - Menart, Svit
AU  - Šala, Martin
AU  - Hrnjić, Armin
AU  - Jovanovič, Primož
AU  - Ruiz-Zepeda, Francisco
AU  - Gaberšček, Miran
AU  - Hodnik, Nejc
PY  - 2021
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/10146
AB  - Degradation of carbon-supported Pt nanocatalysts in fuel cells and electrolyzers hinders widespread commercialization of these green technologies. Transition between oxidized and reduced states of Pt during fast potential spikes triggers significant Pt dissolution. Therefore, designing Pt-based catalysts able to withstand such conditions is of critical importance. We report here on a strategy to suppress Pt dissolution by using an organic matrix tris(aza)pentacene (TAP) as an alternative support material for Pt. The major benefit of TAP is its potential-dependent conductivity in aqueous media, which was directly evidenced by electrochemical impedance spectroscopy. At potentials below ∼0.45 VRHE, TAP is protonated and its conductivity is improved, which enables supported Pt to run hydrogen reactions. At potentials corresponding to Pt oxidation/reduction (>∼0.45 VRHE), TAP is deprotonated and its conductivity is restricted. Tunable conductivity of TAP enhanced the durability of the Pt/TAP with respect to Pt/C when these two materials were subjected to the same degradation protocol (0.1 M HClO4 electrolyte, 3000 voltammetric scans, 1 V/s, 0.05-1.4 VRHE). The exceptional stability of Pt/TAP composite on a nanoscale level was confirmed by identical location TEM imaging before and after the used degradation protocol. Suppression of transient Pt dissolution from Pt/TAP with respect to the Pt/C benchmark was directly measured in a setup consisting of an electrochemical flow cell connected to inductively coupled plasma-mass spectrometry.
T2  - ACS Omega
T1  - Suppressing Platinum Electrocatalyst Degradation via a HighSurface-Area Organic Matrix Support
VL  - 7
IS  - 4
SP  - 3540
EP  - 3548
DO  - 10.1021/acsomega.1c06028
ER  - 

@article{
author = "Smiljanić, Milutin Lj. and Bele, Marjan and Moriau, Léonard Jean and Vélez Santa, John Fredy and Menart, Svit and Šala, Martin and Hrnjić, Armin and Jovanovič, Primož and Ruiz-Zepeda, Francisco and Gaberšček, Miran and Hodnik, Nejc",
year = "2021",
abstract = "Degradation of carbon-supported Pt nanocatalysts in fuel cells and electrolyzers hinders widespread commercialization of these green technologies. Transition between oxidized and reduced states of Pt during fast potential spikes triggers significant Pt dissolution. Therefore, designing Pt-based catalysts able to withstand such conditions is of critical importance. We report here on a strategy to suppress Pt dissolution by using an organic matrix tris(aza)pentacene (TAP) as an alternative support material for Pt. The major benefit of TAP is its potential-dependent conductivity in aqueous media, which was directly evidenced by electrochemical impedance spectroscopy. At potentials below ∼0.45 VRHE, TAP is protonated and its conductivity is improved, which enables supported Pt to run hydrogen reactions. At potentials corresponding to Pt oxidation/reduction (>∼0.45 VRHE), TAP is deprotonated and its conductivity is restricted. Tunable conductivity of TAP enhanced the durability of the Pt/TAP with respect to Pt/C when these two materials were subjected to the same degradation protocol (0.1 M HClO4 electrolyte, 3000 voltammetric scans, 1 V/s, 0.05-1.4 VRHE). The exceptional stability of Pt/TAP composite on a nanoscale level was confirmed by identical location TEM imaging before and after the used degradation protocol. Suppression of transient Pt dissolution from Pt/TAP with respect to the Pt/C benchmark was directly measured in a setup consisting of an electrochemical flow cell connected to inductively coupled plasma-mass spectrometry.",
journal = "ACS Omega",
title = "Suppressing Platinum Electrocatalyst Degradation via a HighSurface-Area Organic Matrix Support",
volume = "7",
number = "4",
pages = "3540-3548",
doi = "10.1021/acsomega.1c06028"
}

Smiljanić, M. Lj., Bele, M., Moriau, L. J., Vélez Santa, J. F., Menart, S., Šala, M., Hrnjić, A., Jovanovič, P., Ruiz-Zepeda, F., Gaberšček, M.,& Hodnik, N.. (2021). Suppressing Platinum Electrocatalyst Degradation via a HighSurface-Area Organic Matrix Support. in ACS Omega, 7(4), 3540-3548.
https://doi.org/10.1021/acsomega.1c06028

Smiljanić ML, Bele M, Moriau LJ, Vélez Santa JF, Menart S, Šala M, Hrnjić A, Jovanovič P, Ruiz-Zepeda F, Gaberšček M, Hodnik N. Suppressing Platinum Electrocatalyst Degradation via a HighSurface-Area Organic Matrix Support. in ACS Omega. 2021;7(4):3540-3548.
doi:10.1021/acsomega.1c06028 .

Smiljanić, Milutin Lj., Bele, Marjan, Moriau, Léonard Jean, Vélez Santa, John Fredy, Menart, Svit, Šala, Martin, Hrnjić, Armin, Jovanovič, Primož, Ruiz-Zepeda, Francisco, Gaberšček, Miran, Hodnik, Nejc, "Suppressing Platinum Electrocatalyst Degradation via a HighSurface-Area Organic Matrix Support" in ACS Omega, 7, no. 4 (2021):3540-3548,
https://doi.org/10.1021/acsomega.1c06028 . .

TY  - JOUR
AU  - Vélez Santa, John Fredy
AU  - Menart, Svit
AU  - Bele, Marjan
AU  - Ruiz-Zepeda, Francisco
AU  - Jovanovič, Primož
AU  - Jovanovski, Vasko
AU  - Šala, Martin
AU  - Smiljanić, Milutin Lj.
AU  - Hodnik, Nejc
PY  - 2021
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/9844
AB  - Developing a Pt-based electrocatalytic material able to selectively catalyze hydrogen oxidation (HOR) while supressing oxygen reduction (ORR) is beneficial for durability of the fuel cells. Namely, degradation of carbon supported Pt particles is dramatically influenced by the unwanted ORR enrolling at the anode due to the air penetration during start-up/shut-down events. We present an organic matrix tris(aza)pentacene (TAP), which belongs to π-functional materials with ladder-like conjugated nitrogen-containing units, as the support for Pt to form a “smart” fuel cell anode able to selectively catalyze HOR and to suppress ORR. “Switching-on/off” of the composite material activity is provided by reversible reduction/oxidation of the TAP in the low potential region which provokes TAP - HxTAP transition. Conductivity of the reduced HxTAP enables supported Pt particles to effectively run HOR. In contrast, restricted conductivity of oxidized TAP analogue leads to the substantial drop in the ORR activity with respect to benchmark Pt/C catalyst.
T2  - International Journal of Hydrogen Energy
T1  - High-surface-area organic matrix tris(aza)pentacene supported platinum nanostructures as selective electrocatalyst for hydrogen oxidation/evolution reaction and suppressive for oxygen reduction reaction
VL  - 46
IS  - 49
SP  - 25039
EP  - 25049
DO  - 10.1016/j.ijhydene.2021.05.041
ER  - 

@article{
author = "Vélez Santa, John Fredy and Menart, Svit and Bele, Marjan and Ruiz-Zepeda, Francisco and Jovanovič, Primož and Jovanovski, Vasko and Šala, Martin and Smiljanić, Milutin Lj. and Hodnik, Nejc",
year = "2021",
abstract = "Developing a Pt-based electrocatalytic material able to selectively catalyze hydrogen oxidation (HOR) while supressing oxygen reduction (ORR) is beneficial for durability of the fuel cells. Namely, degradation of carbon supported Pt particles is dramatically influenced by the unwanted ORR enrolling at the anode due to the air penetration during start-up/shut-down events. We present an organic matrix tris(aza)pentacene (TAP), which belongs to π-functional materials with ladder-like conjugated nitrogen-containing units, as the support for Pt to form a “smart” fuel cell anode able to selectively catalyze HOR and to suppress ORR. “Switching-on/off” of the composite material activity is provided by reversible reduction/oxidation of the TAP in the low potential region which provokes TAP - HxTAP transition. Conductivity of the reduced HxTAP enables supported Pt particles to effectively run HOR. In contrast, restricted conductivity of oxidized TAP analogue leads to the substantial drop in the ORR activity with respect to benchmark Pt/C catalyst.",
journal = "International Journal of Hydrogen Energy",
title = "High-surface-area organic matrix tris(aza)pentacene supported platinum nanostructures as selective electrocatalyst for hydrogen oxidation/evolution reaction and suppressive for oxygen reduction reaction",
volume = "46",
number = "49",
pages = "25039-25049",
doi = "10.1016/j.ijhydene.2021.05.041"
}

Vélez Santa, J. F., Menart, S., Bele, M., Ruiz-Zepeda, F., Jovanovič, P., Jovanovski, V., Šala, M., Smiljanić, M. Lj.,& Hodnik, N.. (2021). High-surface-area organic matrix tris(aza)pentacene supported platinum nanostructures as selective electrocatalyst for hydrogen oxidation/evolution reaction and suppressive for oxygen reduction reaction. in International Journal of Hydrogen Energy, 46(49), 25039-25049.
https://doi.org/10.1016/j.ijhydene.2021.05.041

Vélez Santa JF, Menart S, Bele M, Ruiz-Zepeda F, Jovanovič P, Jovanovski V, Šala M, Smiljanić ML, Hodnik N. High-surface-area organic matrix tris(aza)pentacene supported platinum nanostructures as selective electrocatalyst for hydrogen oxidation/evolution reaction and suppressive for oxygen reduction reaction. in International Journal of Hydrogen Energy. 2021;46(49):25039-25049.
doi:10.1016/j.ijhydene.2021.05.041 .

Vélez Santa, John Fredy, Menart, Svit, Bele, Marjan, Ruiz-Zepeda, Francisco, Jovanovič, Primož, Jovanovski, Vasko, Šala, Martin, Smiljanić, Milutin Lj., Hodnik, Nejc, "High-surface-area organic matrix tris(aza)pentacene supported platinum nanostructures as selective electrocatalyst for hydrogen oxidation/evolution reaction and suppressive for oxygen reduction reaction" in International Journal of Hydrogen Energy, 46, no. 49 (2021):25039-25049,
https://doi.org/10.1016/j.ijhydene.2021.05.041 . .

TY  - JOUR
AU  - Smiljanić, Milutin Lj.
AU  - Petek, Urša
AU  - Bele, Marjan
AU  - Ruiz-Zepeda, Francisco
AU  - Šala, Martin
AU  - Jovanovič, Primož
AU  - Gaberšček, Miran
AU  - Hodnik, Nejc
PY  - 2021
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/9548
AB  - Electrochemical stability of a commercial Au/C catalyst in an acidic electrolyte has been investigated by an accelerated stress test (AST), which consisted of 10,000 voltammetric scans (1 V/s) in the potential range between 0.58 and 1.41 VRHE. Loss of Au electrochemical surface area (ESA) during the AST pointed out to the degradation of Au/C. Coupling of an electrochemical flow cell with ICP-MS showed that only a minor amount of gold is dissolved despite the substantial loss of gold ESA during the AST (∼35% of initial value remains at the end of the AST). According to the electrochemical mass spectrometry experiments, carbon corrosion occurs during the AST but to a minor extent. By using identical location scanning electron microscopy and identical location transmission electron microscopy, it was possible to discern that the dissolution of small Au particles (<5 nm) within the polydisperse Au/C sample is the main degradation mechanism. The mass of such particles gives only a minor contribution to the overall Au mass of the polydisperse sample while giving a major contribution to the overall ESA, which explains a significant loss of ESA and minor loss of mass during the AST. The addition of low amounts of chloride anions (10-4 M) substantially promoted the degradation of gold nanoparticles. At an even higher concentration of chlorides (10-2 M), the dissolution of gold was rather effective, which is useful from the recycling point of view when rapid leaching of gold is desirable. © 2021 American Chemical Society.
T2  - The Journal of Physical Chemistry C
T1  - Electrochemical Stability and Degradation Mechanisms of Commercial Carbon-Supported Gold Nanoparticles in Acidic Media
VL  - 125
IS  - 1
SP  - 635
EP  - 647
DO  - 10.1021/acs.jpcc.0c10033
ER  - 

@article{
author = "Smiljanić, Milutin Lj. and Petek, Urša and Bele, Marjan and Ruiz-Zepeda, Francisco and Šala, Martin and Jovanovič, Primož and Gaberšček, Miran and Hodnik, Nejc",
year = "2021",
abstract = "Electrochemical stability of a commercial Au/C catalyst in an acidic electrolyte has been investigated by an accelerated stress test (AST), which consisted of 10,000 voltammetric scans (1 V/s) in the potential range between 0.58 and 1.41 VRHE. Loss of Au electrochemical surface area (ESA) during the AST pointed out to the degradation of Au/C. Coupling of an electrochemical flow cell with ICP-MS showed that only a minor amount of gold is dissolved despite the substantial loss of gold ESA during the AST (∼35% of initial value remains at the end of the AST). According to the electrochemical mass spectrometry experiments, carbon corrosion occurs during the AST but to a minor extent. By using identical location scanning electron microscopy and identical location transmission electron microscopy, it was possible to discern that the dissolution of small Au particles (<5 nm) within the polydisperse Au/C sample is the main degradation mechanism. The mass of such particles gives only a minor contribution to the overall Au mass of the polydisperse sample while giving a major contribution to the overall ESA, which explains a significant loss of ESA and minor loss of mass during the AST. The addition of low amounts of chloride anions (10-4 M) substantially promoted the degradation of gold nanoparticles. At an even higher concentration of chlorides (10-2 M), the dissolution of gold was rather effective, which is useful from the recycling point of view when rapid leaching of gold is desirable. © 2021 American Chemical Society.",
journal = "The Journal of Physical Chemistry C",
title = "Electrochemical Stability and Degradation Mechanisms of Commercial Carbon-Supported Gold Nanoparticles in Acidic Media",
volume = "125",
number = "1",
pages = "635-647",
doi = "10.1021/acs.jpcc.0c10033"
}

Smiljanić, M. Lj., Petek, U., Bele, M., Ruiz-Zepeda, F., Šala, M., Jovanovič, P., Gaberšček, M.,& Hodnik, N.. (2021). Electrochemical Stability and Degradation Mechanisms of Commercial Carbon-Supported Gold Nanoparticles in Acidic Media. in The Journal of Physical Chemistry C, 125(1), 635-647.
https://doi.org/10.1021/acs.jpcc.0c10033

Smiljanić ML, Petek U, Bele M, Ruiz-Zepeda F, Šala M, Jovanovič P, Gaberšček M, Hodnik N. Electrochemical Stability and Degradation Mechanisms of Commercial Carbon-Supported Gold Nanoparticles in Acidic Media. in The Journal of Physical Chemistry C. 2021;125(1):635-647.
doi:10.1021/acs.jpcc.0c10033 .

Smiljanić, Milutin Lj., Petek, Urša, Bele, Marjan, Ruiz-Zepeda, Francisco, Šala, Martin, Jovanovič, Primož, Gaberšček, Miran, Hodnik, Nejc, "Electrochemical Stability and Degradation Mechanisms of Commercial Carbon-Supported Gold Nanoparticles in Acidic Media" in The Journal of Physical Chemistry C, 125, no. 1 (2021):635-647,
https://doi.org/10.1021/acs.jpcc.0c10033 . .