Trifunctional Electrocatalysts for the Hydrogen Evolution Reaction (HER), Oxygen Evolution Reaction (OER), and Urea Oxidation Reaction (UOR)

Abstract

The quest for alternative fuels has been investigated for many years owing to the storage constraints on fossil fuels and petroleum and the excessive carbon dioxide emissions following combustion. Recently, the use of hydrogen as a fuel has attracted substantial attention. Electrochemical water splitting has gained prominence as a crucial method of production that can be utilized to create clean hydrogen fuel that is sustainable, renewable, affordable, and efficient. Trifunctional electrocatalysts are substances with simultaneous catalytic activity for many electrochemical processes. Several energy conversion and storage applications require the simultaneous electrocatalytic activities of the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and an additional reaction, such as the urea oxidation reaction (UOR), which is why the design of such catalysts is of great interest. This chapter introduces the basic principles of electrochemical water splitting along with a detailed explanation of HER-, OER-, and UOR-based water-splitting mechanisms. How heteroatom doping, heterostructures, cocatalyst deposition, and surface modification can improve hydrogen generation is discussed, and the factors that affect the electrochemical performance are also examined. A promising research field with enormous potential for a range of energy conversion and storage applications is the creation of effective trifunctional electrocatalysts.