F-Doped Co₃O₄ Photocatalysts for Sustainable H₂ Generation from Water/Ethanol

Abstract

p-Type Co(3)O(4) nanostructured films are synthesized by a plasma-assisted process and tested in the photocatalytic production of H(2) from water/ethanol solutions under both near-UV and solar irradiation. It is demonstrated that the introduction of fluorine into p-type Co(3)O(4) results in a remarkable performance improvement with respect to the corresponding undoped oxide, highlighting F-doped Co(3)O(4) films as highly promising systems for hydrogen generation. Notably, the obtained yields were among the best ever reported for similar semiconductor-based photocatalytic processes.

Water interaction with perfect and fluorine-doped Co3O4 (100) surface

“…We found also that at the Co 5c O site on fluorine-doped surface theoretical overpotential on the Co 3 O 4 (100) surface is considerably reduced, from 0.81 to 0.44 V. Due to large overpotential, the OER efficiency on the pure Co 3 O 4 substrate is expected to be low and thus F doping does improve it. This implies that fluorine-doped Co 3 O 4 is active for electrochemical oxidation of water, in full agreement with experimental observations [10]. In the forthcoming paper we will discuss cation, Cs doping effects.…”

“…It is also well known that the presence of different promoters in p-type semiconducting photocatalysts, such as Co 3 O 4 , could lead to a significant decrease of the OER overpotential [9]. Indeed, in an experimental study by Gasparotto et al [10] anion, F-doping of nanostructured films of Co 3 O 4 resulted in a significant improvement of catalytic properties. It is expected that this is related to an increase of concentration of Co 2+ active centers.…”

Photocatalytic Properties of Co3O4-Coated TiO2 Powders Prepared by Plasma-Enhanced Atomic Layer Deposition

“…Co 3 O 4 , one of the most versatile transition-metal oxides, is widely applied in many fields, such as dyes degradation [23, 24], gas sensors [25], lithium ion batteries [26], oxidation of CO at low temperature [27], and H 2 generation [28]. Co 3 O 4 , like NiO and Ag 2 O, belongs to p-type semiconductors.…”

Fluorine-Doped Iron Oxide Nanomaterials by Plasma Enhanced-CVD: An XPS Study

“…[1][2][3][4][5][6][7][8][9]. In this context, iron(III) oxides (Fe 2 O 3 ) have been the focus of intensive research efforts thanks to their accessibility to different polymorphs (a, b, c, and e being the most common), variety of electronic/magnetic properties, ample abundance and biocompatibility.…”

“…Among the various Fe 2 O 3 technological applications, photo-catalytic solar hydrogen production from renewable resources has emerged as a key applicative option for a sustainable energy production (Refs. [1][2][3]. To this aim, most of the studies have been devoted to hematite (a-Fe 2 O 3 ) as photo-catalyst, whose main shortcomings are the low absorption coefficient and high carrier recombination rate (Refs.…”