Influence of graphitic materials microstructure in the hydrogen evolution in aqueous solution of tetra-alkylammonium-sulfonic acid ionic liquid

Lima, Demétrius W.; Fiegenbaum, Fernanda; Trombetta, Fernanda; Souza, Michèle Oberson de; Martini, Emilse Maria Agostini

doi:10.1016/j.ijhydene.2017.11.097

Cited by 9 publications

(17 citation statements)

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“…The generation and desorption of these H 2 nanobubbles can promote a dynamic equilibrium resulting in a cathodic current limit . A similar plateau was also observed in PC and VC . When the HER is performed in carbon materials, nanobubbles are formed in the proximity of defects of the graphitic plane, such as edges and atomic steps .…”

Section: Resultsmentioning

confidence: 55%

“…The presence of Ni particles in the VC caused an increase of both R 1 and R 2 , that is, it hampered both the H + adsorption with charge transfer process and the H 2 desorption. Still, the more ordered and crystalline microstructure of the PC apparently makes the H + adsorption in the Volmer step more difficult, as indicated by the higher value of R 2 . Conversely, R 1 and R 2 values decreased for Ni/PC, indicating that the presence of Ni particles on PC facilitates the charge transfer process and generates the lower bond energy of the H 2 gas with the electrocatalyst surface.…”

Section: Resultsmentioning

confidence: 99%

“…The E a values to the Ni/PC (11.1 kJ mol −1 ) and the Ni/VC (15.4 kJ mol −1 ) cathodes are higher than those obtained with carbon cathodes without Ni . The linear voltammetry analysis was performed in order to determine the open‐circuit potential ( E OCP ) and the exchange current density at the open‐circuit potential ( i 0 ) as well as the HER mechanism.…”

Section: Resultsmentioning

confidence: 99%

“…When the adsorption step (Volmer step, Equation ) is the slow step of the process, the Tafel constant for all cathodic overpotentials will be −120 mV dec −1 . When the slow step of the reaction mechanism of the HER is the desorption through the Heyrovsky step (Equation ), then the Tafel constant in low cathodic potentials will be −40 mV dec −1 , and for high cathodic overpotentials the Tafel constant will be also −120 mV dec −1 . However, when the slow step of the HER mechanism is a Tafel step (Equation ), then the Tafel constant observed for low cathodic overpotentials is 30 mV dec −1 , and for high cathodic overpotentials the current density will not depend on η C .…”

Section: Resultsmentioning

confidence: 99%

“…According to Table , the HER carried out on the Ni/VC and Ni/PC cathodes presents smaller open‐circuit potential ( E OCP ) and greater exchange current density ( i 0 ) than those in VC and PC cathodes . Therefore, the modification of the carbon material with Ni particles increases the number of active sites, probably because it facilitates desorption of H 2 gas.…”

Section: Resultsmentioning

confidence: 99%

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Effect of different carbon supports for Ni particles for the HER in tetra‐alkylammonium‐sulfonic acid media

et al. 2019

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Summary Vitreous carbon (VC) and pyrolytic carbon (PC) were covered by nickel particles through sputter deposition, consisting in the Ni/VC and Ni/PC electrodes, respectively. These materials were tested as cathodes in an aqueous solution of tetrafluoroborate of the 3‐triethylammonium‐propane sulfonic acid ionic liquid (TEA‐PS.BF4) for hydrogen production and characterized by scanning electron microscopy (SEM), chronoamperometry (CA), linear and cyclic voltammetry (LV and CV), and electrochemical impedance spectroscopy (EIS). The mechanism of the hydrogen evolution reaction (HER) was that of Volmer‐Heyrovsky for all the cathodes tested, and the H2 desorption at the catalytic surface is the determining step. The results indicate that different carbon supports can affect the efficiency of the particulate electrocatalyst deposited on it. The low values of H+ adsorption and the H2 desorption resistances of the modified PC system (0.43 and 0.8 Ω cm2, respectively), in relation to the modified VC system (1.13 and 7.9 Ω cm2, respectively), attest that Ni particles presence on PC favored the adsorption of H+ and H2 nanobubble desorption. The Ni particles on PC increase exchange current density (80.5 μA cm2 for Ni/PC cathode about 38.3 Ω cm2 for Ni/VC cathode) and enhance catalytic activity. These results can be attributed to the faster liberation of the active sites due to the interaction between the Ni particles and the PC support. In addition, the TEA‐PS.BF4 solution can act as a stripper, avoiding the formation of passive oxides in the open circuit and preventing the deactivation of the electrocatalyst.

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Section: Resultsmentioning

confidence: 55%

Section: Resultsmentioning

confidence: 99%