Developments in cobalt-based soft materials as electrocatalysts for oxygen evolution reaction

초록

The search for sustainable, clean, and highly efficient energy sources is underway at a faster phase to meet the energy needs of modern society. Among the various sustainable energy technologies, water electrolysis emerges as a promising approach to pave the way for tomorrow's green energy fulfilment. In water electrolysis, hydrogen evolves on the cathode side, and oxygen evolves on the anode side. The oxygen evolution reaction (OER) process is crucial as it is highly sluggish compared to the hydrogen evolution reaction (HER) towards efficient, clean and green energy production. The traditional benchmark catalysts such as IrO2 and RuO2 face challenges of high cost and limited abundance. Therefore, the search for efficient and cost-effective alternate electrocatalysts has been intensified. To improve the gas evolution efficiency, researchers have developed numerous advanced electrocatalysts, leading to significant progress in understanding the fundamental mechanism of the OER and essential requirements of a good electrocatalyst. This review inspects the current progress in the electrocatalysis of OER. It presents the theoretical principles and critical parameters for evaluating OER catalysts. Then, latest developments in catalyst materials for performing OER activity, including precious and non-precious materials have been discussed. Further, a thorough review of the Co-based-N4 macromolecules for OER applications has been carried out with respect to the simplicity of synthesis and ability to fine-tune their electronic properties through the substitution of axial/peripheral groups. Attention is also paid to the single atom catalyst (SAC) approach for attaining significant electrocatalytic behavior for OER. The mechanism of OER has been enumerated from the perspective of recent experimental studies. Finally, the strategies for improving the OER performance for future research are presented.

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