Introduction to Electrocatalysts
Pravallika Banoth, Chinna Kandula, Pratap Kollu
Abstract
With global energy consumption growing at an unprecedented rate and environmental concerns becoming increasingly acute, the need for clean, sustainable energy conversion and storage systems such as fuel cells, dye-sensitized solar cells, metal-air batteries and Li-CO2 batteries is of utmost significance. The main reactions involved in these renewable energy technologies are oxygen reduction reaction (ORR), oxygen evolution reaction (OER), hydrogen evolution reaction (HER), and CO2 reduction reaction (CO2RR), which all require catalysts. An electrocatalyst is a surface where chemical energy is electrochemically converted into electrical energy in fuel cells. For the selection of an electrocatalyst and tailoring its characteristics, both stability and selectivity must be assessed. Overall fuel cell performance is mainly determined by the efficiency of the electrocatalyst. Catalysts based on metals are currently widely used, but they suffer from multiple competitive disadvantages, including their low selectivity, poor durability, and negative environmental impact. Hence, it is highly desirable to develop earth-abundant, low-cost, stable, and catalytically active metal-free alternatives for application in renewable energy. Catalysts made from carbon-based metal-free materials possess advantages such as high earth abundance, low cost, high electrical conductivity, structural tunability, good selectivity, and solid stability in acid/alkaline conditions. These characteristics explain why these catalysts are receiving increasing attention in applications related to energy and the environment. Through electrocatalysis without the use of noble metals, numerous carbon-based electrocatalysts have been developed for the storage of clean energy and the protection of the environment. This chapter aims to introduce electrocatalysts and electrocatalysis to the reader. By understanding electrocatalysis and electrocatalysts, the readers will gain a deeper understanding of the concepts. Firstly, the authors will discuss the basics of electrocatalysts, electrocatalysis, types of electrocatalysts, and electrocatalysis, and then they will review some fundamental concepts. Lastly, a brief overview of recent research and advancements in non-noble metal free electrocatalysts will be presented by using carbon-based nanomaterials in the context of energy storage and concluded with a remark.