0000000000241065
AUTHOR
Martín Mizrahi
Crystallographic and geometrical dependence of water oxidation activity in Co-based layered hydroxides
Cobalt-based layered hydroxides (LHs) stand out as one of the best families of electroactive materials for the alkaline oxygen evolution reaction (OER). However, fundamental aspects such as the influence of the crystalline structure and its connection with the geometry of the catalytic sites remains poorly understood. Thus, to address this we have conducted a thorough experimental and in silico study on the most essential Co-LHs (i.e.: ɑ-LH, β-LH and LDH) which allows us to understand the role of the layered structure and coordination environment of Co atoms on the OER performance. The ɑ-LH, containing both octahedral and tetrahedral sites, behaves as the best OER catalyst in comparison to …
Influence of crystallographic structure and metal vacancies on the oxygen evolution reaction performance of Ni-based layered hydroxides
Nickel-based layered hydroxides (LHs) are a family of efficient electrocatalysts for the alkaline oxygen evolution reaction (OER). Nevertheless, fundamental aspects such as the influence of the crystalline structure and the role of lattice distortion of the catalytic sites remain poorly understood and typically muddled. Herein, we carried out a comprehensive investigation on ɑ-LH, β-LH and LDH phases, analysing the role exerted by Ni-vacancies by means of structural, spectroscopical, in-silico and electrochemical studies. Indeed, density functional theory (DFT) calculations, in agreement with X-ray absorption spectroscopy (XAS), confirm that the presence of Ni-vacancies produces acute disto…
Unveiling the Occurrence of Co(III) in NiCo Layered Electroactive Hydroxides: The Role of Distorted Environments
Co- and Ni-based layered hydroxides constitute a unique class of two-dimensional inorganic materials with exceptional chemical diversity, physicochemical properties and outstanding performance as supercapacitors and overall water splitting catalysts. Recently, the occurrence of Co(III) in these phases has been proposed as a key factor that enhance their electrochemical performance. However, the origin of this centers and control over its contents remains as an open question. We employed the Epoxide Route to synthesize a whole set of α-NiCo layered hydroxides. The PXRD and XAS characterization alert about the occurrence of Co(III) as a consequence of the increment in the Ni content. DFT+U si…