Emerging trends of electrocatalytic technologies for renewable hydrogen energy from seawater: Recent advances, challenges, and techno-feasible assessment

Hydrogen has been regarded as a promising renewable and green energy source to meet energy needs and attain net-zero carbon emissions. The electrolysis of seawater to make hydrogen is one of the fascinating developments of the twenty-first century. This method uses abundant and relatively inexpensive seawater, as opposed to freshwater, which is rare and can be prohibitively expensive. In recent years, significant research and advancements have been made in direct seawater electrolysis technology for hydrogen production. However, producing highly effective and efficient electrocatalysts with long-term viability under harsh corrosive conditions remains a challenging and severe topic for large-scale seawater electrolysis technology. There is still a large accomplishment gap in understanding how to improve seawater electrolysis to increase hydrogen yields and prolong stability. It is, therefore, crucial to have a condensed knowledge of the tunable and inherent interactions between various electrocatalysts, covering electrolyzer types and paying particular attention to those with high efficiency, chemical stability, and conductivity. The extensive discussion is structured into a progression from noble metals to base metal compounds such as oxides, alloys, phosphides, chalcogenides, hydroxides, and nitrides, MXene-based complexes with a concise examination of hybrid electrocatalysts. In addition, proton exchange membranes, anion exchange membranes, alkaline water electrolyzers, and high-temperature water electrolyzers were potential contributors to seawater's electrolysis. An extensive assessment of the techno-feasibility, economic insights, and future suggestions was done to commercialize the most efficient electrocatalytic systems for hydrogen production. This review is anticipated to provide academics, environmentalists, and industrial researchers with valuable ideas for constructing and modifying seawater-based electrocatalysts.