Hierarchical Co(OH)F Superstructure Built by Low‐Dimensional Substructures for Electrocatalytic Water Oxidation

Abstract

The development of new materials/structures for efficient electrocatalytic water oxidation, which is a key reaction in realizing artificial photosynthesis, is an ongoing challenge. Herein, a Co(OH)F material as a new electrocatalyst for the oxygen evolution reaction (OER) is reported. The as-prepared 3D Co(OH)F microspheres are built by 2D nanoflake building blocks, which are further woven by 1D nanorod foundations. Weaving and building the substructures (1D nanorods and 2D nanoflakes) provides high structural void porosity with sufficient interior space in the resulting 3D material. The hierarchical structure of this Co(OH)F material combines the merits of all material dimensions in heterogeneous catalysis. The anisotropic low-dimensional (1D and 2D) substructures possess the advantages of a high surface-to-volume ratio and fast charge transport. The interconnectivity of the nanorods is also beneficial for charge transport. The high-dimensional (3D) architecture results in sufficient active sites per the projected electrode surface area and is favorable for efficient mass diffusion during catalysis. A low overpotential of 313 mV is required to drive an OER current density of 10 mA cm on a simple glassy carbon (GC) working electrode in a 1.0 m KOH aqueous solution.

Porous Hollow‐Structured LaNiO3 Stabilized N,S‐Codoped Graphene as an Active Electrocatalyst for Oxygen Reduction Reaction

“…But the high cost, easy CO poisoning, coarsening possibility, and ready defeat from the cathode lead to decrease in the electrochemical surface area of Pt, and hence its catalytic activity . For developing inexpensive, stable, and highly efficient electrocatalysts, ongoing efforts are focused on abundant and nonprecious metal‐based nanomaterials . As a consequence, lot of unique architectures, such as pyrochlore, spinel, fergusonite, fluorite, ruddlesden‐popper, perovskite, and apatites, have been considered as prospectively valuable approaches for electrocatalytic applications .…”

Engineering Ternary Pyrite‐Type CoPS Nanosheets with an Ultrathin Porous Structure for Efficient Electrocatalytic Water Splitting

“…The peaks at 780.1 and 795.4 eV are attributed to the Co 3 + of CoOOH. [38,39] Another peak at 532.4 eV is assigned to the higher covalence of surface hydroxyls. The PÀ O bond and SÀ O bond become dominant in the P 2p spectra and S 2p spectra ( Figure S13b and c) respectively, indicating electrochemical oxidation during the OER process.…”

Porous Materials as Highly Efficient Electrocatalysts for the Oxygen Evolution Reaction

“…[6] As as luggish half-reaction of water electrolysis, the oxygen evolution reaction (OER) is the bottleneck for water splitting. [17] The former two aspects are relatedtothe intrinsicc hemical properties of the materials,a nd the latter two issues are subject to the microcosmic physicalstructures of the materials. [10][11][12] Av ariety of solid materials has been reported as OER electrocatalysts in electrolytes with different pHs.…”

“…[27,28] Owing to the unique physicala nd chemical characteristics different from bulk materials, porousm aterials have also been widely appliedi ne lectrocatalysis, which is ah eterogeneous process happening on the interface. [17] The building of low-dimensional substructures (1D nanorods and 2D nanoflakes) brought about abundant open spacesi nt he resulting 3D structure. There are three general approaches to construct pores in electrodes.…”