Nano Tungsten Disulfide Can Be Used to Produce Hydrogen from Seawater

Although sunlight is a clean energy source, many problems hinder its widespread use. The most important is its intermittence, which is not always sunny, and sunny periods are not always highly correlated with electricity demand. In addition, if the electricity generated by solar energy cannot be used or stored immediately, it will be wasted. Therefore, there is a need for a practical way to store solar energy, which can be used when needed. These means can make people use solar energy and hydrogen energy more efficiently and further reduce their dependence on oil.

Hydrogen production from seawater electrolysis has long existed, but the need for large amounts of electricity and expensive catalysts has led to high costs and popularization. The main cost is the precious metal catalyst platinum. In most hydrogen conversion, platinum metal is considered to be the best catalyst. But platinum is so expensive that people need to find cheap and efficient catalytic materials to break through the cost bottleneck of seawater hydrogen production technology.

A scientific team from the United States is working on a new type of electrocatalyst and has found a new material for catalysis, tungsten disulfide nanosheet. This two-dimensional material, similar to graphene, has a dense hexagonal layered structure. Its crystal is composed of three S-W-S planes. Each S atom in the layer is equal to the surrounding S-W atoms, and each W atom is equal to that of the surrounding S-W atoms. The six sulfur atoms around them form a prism coordination unit structure and a hexagonal crystal layered structure with excellent electrical properties.

In tungsten disulfide, the interaction between W atom in the layer and S atom around it is very strong, but the interaction between W atom in the layer and S atom in the layer is very weak. This characteristic enables nano tungsten disulfide to stand out from molybdenum disulfide, titanium dioxide or its materials. Electricity generated by scientists from renewable sources of energy, such as solar cells or wind turbines, can be transferred to tungsten sulfide sheets through conductive support materials. Current enters the catalytic edge of the sheet, where it is transferred to water molecules, splitting them into oxygen and hydrogen.

Scientists are transferring electricity to tungsten disulfide sheets through support materials. They changed the structure of supporting materials, changed the supporting materials that were usually flat to the surface perpendicular to the surface, and adjusted the chemical composition of the edges to make the power transmission more efficient.

Scientists believe that the results of their project are more practical and may have an impact on clean energy in the future, but they still have many problems to solve, most importantly the storage of electricity.

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