Morphology alteration of nickel microstructures for glycerol electrooxidation

HOUACHE, MOHAMED S.E.; SANDOVAL, MARIO G.; SAFARI, REZA; GAZTAÑAGA, FRANCISCO; ESCUDERO, FEDERICO; HERNÁNDEZ-LAGUNA, ALFONSO; SAINZ-DÍAZ, CLARO IGNACIO; BOTTON, GIANLUIGI A.; JASEN, PAULA V.; GONZÁLEZ, ESTELA A.; JUAN, ALFREDO; BARANOVA, ELENA A.

JOURNAL OF CATALYSIS

ACADEMIC PRESS INC ELSEVIER SCIENCE

Año: 2021 vol. 404 p. 348 - 361

0021-9517

Shape-controlled microstructures (triangles and urchin-like) of Ni were synthesized using polyol synthesis in the presence/absence of capping agent (polyvinilpyrrolidone, PVP). Direct visualization of crystal structure and morphology before/after electrochemical tests in KOH were characterized using electron microscopy techniques. Electrochemical characterizations illustrated that urchin-Ni-PVP has highest catalytic activity among all investigated electrocatalysts for glycerol electrooxidation reaction (GEOR). Improved activity was attributed to the surface area and the highly porous structure as identified by electron tomography analysis. All Ni shapes showed similar selectivity. DFT calculations on low-index β-NiOOH and β-Ni(OH)2 planes were performed as possible surfaces present during electrochemical processes. The (0 0 1) surface is the most thermodynamically stable in both systems and has different possible terminations. For O, Ni and mixed Ni-O atoms terminations the β-NiOOH(0 0 1) present metallic behavior. DFT results show that either Ni or Ni-O exposed β-NiOOH(0 0 1) surfaces are possible scenarios for glycerol adsorption on different catalytic charged surface sites.