The Central Role of Nitrogen Atoms in a Zeolitic Imidazolate Framework-Derived Catalyst for Cathodic Hydrogen Evolution.
ChemSusChem
; 14(18): 3926-3934, 2021 Sep 20.
Article
em En
| MEDLINE
| ID: mdl-34288529
ABSTRACT
Platinum usually offers the most effective active center for hydrogen evolution reaction (HER), because of the optimal trade-off between the adsorption and desorption of hydrogeNâ
atoms (H*) on Pt atoms. Herein, we report an unusual result regarding the active center of aâ
HER catalyst, which was synthesized by electrodepositing traces of Pt nanoparticles (NPs) into a porous nitrogen-rich dodecahedron matrix derived from zeolitic imidazolate framework ZIF-8. With an ultra-low Pt loading of 2.76â
µg cm-2 , the N-Pt-bonded catalyst can produce a current density of 117â
mA cm-2 for the HER in 1.0â
m H2 SO4 at an overpotential of 50â
mV, whereas the commercial Pt/C (300â
µg cm-2 Pt) can only reach 50â
mA cm-2 under the same conditions. Cyclic voltammetry demonstrates that both the H* adsorption and the Pt oxidation are not allowed to occur on this catalyst, due to aâ
full surface coverage of the trace Pt NPs by imidazole. The results from the specially designed experiments indicate that the imidazole Nâ
atoms may act as proton anchor-sites for the HER due to their electron donor nature. Density functional theory calculations also support aâ
catalytic HER mechanism centered at the Pt-supported N active center, which needs aâ
Gibbs free energy of H* absorption (ΔGH* ) significantly smaller than the absolute value of ΔGH* on the Pt(111) surface. We hope that the results of this study will encourage the research on novel N-centered catalysts for the HER.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
ChemSusChem
Assunto da revista:
QUIMICA
/
TOXICOLOGIA
Ano de publicação:
2021
Tipo de documento:
Article