With the rapid rise of global energy demand and the increasing problem of greenhouse gas emissions, the deployment of hydrogen energy industry has become one of the important strategies to solve the sustainable development of society, economy and environment. Hydrogen is widely used to synthesize and upgrade liquid fuels to replace traditional petroleum to produce gasoline and diesel. Meanwhile, proton exchange membrane fuel cells (PEMFCs) fueled with hydrogen have high energy conversion efficiency, and the byproduct is only water, which is expected to become the power core of a new generation of vehicles.

The through hole is one of the important components of PCB. Its function is to fix or locate the electrical connection channels and devices between layers. Mechanical drilling with PCB micro-drill is the most commonly used processing method.

Cadmium selenide nanocrystals are the most widely studied and promising class of II-VI semiconductor nanocrystals. They have attracted worldwide attention due to their important non-linear optical properties, luminescent properties and other physical and chemical properties.

Transition metal chalcogenides, as a new two-dimensional layered material, have similar properties to graphene and are widely used in field-effect transistors, sensors, energy storage and catalysis. Tungsten selenide, as an undeveloped transition metal chalcogenide, is a promising non-noble metal catalyst. Its performance is also influenced by the phase and electronic structure.