Advanced Two-Dimensional Materials for Green Hydrogen Generation: Strategies toward Corrosion Resistance Seawater Electrolysis─Review and Future Perspectives

Abstract

Excessive usage of nonrenewable resources to meet global energy requirements has become a serious concern from the energy and environmental perspective. The continuous emission of CO2 in the environment from fossil fuels has become a major cause of global warming. Green hydrogen generation through seawater electrolysis has been an emergent technology that can play a prominent role in replacing conventional energy sources. Electrolysis of seawater using renewable sources such as solar, wind, and geothermal generates green hydrogen which has almost negligible harmful byproducts. Different ions present in seawater such as chlorides and sulfates impose serious corrosion problems during the electrolysis process as chloride ions penetrate the metal electrode surface and oxidize it and also liberate chlorine gas at the anode. For the electrolysis processes, catalysis plays a challenging task to reduce the kinetic barrier for the conversion of water molecules to hydrogen and oxygen products. Photoelectrocatalysts are another kind of semiconductor-based catalyst in which band gap, exchange charge carrier, and surface area play key roles in the water-splitting process. Two-dimensional nanomaterials offer many advantages like high specific surface area for electron transfer, high tunable functionalities, and flexible structural properties that make them suitable for different applications. Layered double hydroxide (LDH) as a highly efficient catalyst has the potential to perform the hydrogen production process as per the industrial application. LDH has many advantages in an effective water-splitting mechanism that includes easy synthesis methods, flexible morphology, long-term stability, and adaptability to different applications. Another major advantage is the corrosion inhibition property of LDH by different mechanisms like adsorption of corrosion-responsible ions, self-healing technique, and protective film formation which are discussed briefly in this review. This review provides a state-of-the-art analysis about the various important strategies to be adopted for effective seawater electrolysis. Finally, we examine the new challenges and the novel approaches to suppress corrosion processes during seawater electrolysis.