Porous Materials as Highly Efficient Electrocatalysts for the Oxygen Evolution Reaction

Abstract

Carbon‐neutral hydrogen has potential to alleviate the energy crisis and ease environmental problems. Water electrolysis is a sustainable way for large‐scale hydrogen production when electricity is generated from renewable energy resources. The key challenge in water splitting is the sluggish kinetics of the oxygen evolution reaction (OER). Thus, it is important and necessary to develop highly efficient electrocatalysts in a cost‐effective way for OER. Porous materials have proven to be versatile in catalysis due to their large surface area, the fast mass diffusion, and the buffer ability of volume change. Herein, we summarize the recent progress of representative methodologies for the synthesis of porous materials toward electrocatalytic OER. The materials discussed in this Review include the cheap transition‐metal‐based (Co, Ni, and Fe) and metal‐free porous materials. This Review sheds light on the different strategies to construct catalysts with porous structures to facilitate OER.

Importance of Electrocatalyst Morphology for the Oxygen Reduction Reaction

“…Porous materials can be divided into microporous (pore size less than 2 nm), mesoporous (pore size 2–50 nm) and macroporous (pore size greater than 50 nm) materials. Porous materials usually have large surface area, which could afford much more active sites and facilitate the mass/charge transfer during the electrocatalytic process ,. Therefore, 3D porous M−N−C materials also have excellent electrocatalytic activity for ORR .…”

Fluorine‐Doped Tin Oxide/Alumina as Long‐Term Robust Conducting Support for Earth‐Abundant Water Oxidation Electrocatalysts

“…Other current bottleneck in the development of water electrolysis technology is precisely the substitution of this kind of noble, expensive catalysts. Increasing efforts are being made towards the implementation of Earth‐abundant transition‐metal oxides ,. In this context, a cobalt‐analogue of Prussian Blue (PB), cobalt hexacyanoferrate (CoHCF), has been reported as a good candidate as water oxidation catalyst showing an efficient and robust activity .…”

“…[15] In the present study our interest is focused on the application of AAO in water electrolysis, since one of the main bottlenecks in this field is the search for stable electrodes able to survive to challenging redox and pH conditions. [16][17][18] Noble metal electrodes are traditionally used for water oxidation, specially at low pH. [19][20] Ni-based electrodes are preferred at high alkaline pH [8,21] but they rapidly get oxidized when the pH is lowered.…”

“…Increasing efforts are being made towards the implementation of Earthabundant transition-metal oxides. [18,[25][26] In this context, a cobalt-analogue of Prussian Blue (PB), cobalt hexacyanoferrate (CoHCF), has been reported as a good candidate as water oxidation catalyst showing an efficient and robust activity. [27][28][29][30][31][32] Herein we aim to use anodic aluminum oxide as support for Prussian Blue nanoparticles.…”

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

“…[18] Ultrathin twodimensional (2D) nanosheets with atomic thickness have been demonstrated to generate more coordinated-unsaturated active atoms than other nanostructures. [22] Recently, Yan et al synthesized a nonstoichiometric pyrrhotite-type Co 0.9 S 0.58 P 0.42 yolk-shell spheres for the electrocatalytic water splitting, with a 1.59 V cell voltage to provide 10 mA cm À 2 current density. [22] Recently, Yan et al synthesized a nonstoichiometric pyrrhotite-type Co 0.9 S 0.58 P 0.42 yolk-shell spheres for the electrocatalytic water splitting, with a 1.59 V cell voltage to provide 10 mA cm À 2 current density.…”