Good to know you are working in this area of generation of Hydrogen Fuel by Photolysis of water. I worked over it a few years back. Regarding your question there are multiple CAD/CAM softwares available. Most prominent being Solidworks, ProE. CATIA, etc. Out of which most used is SolidWorks. Its simple and easy to learn. For your Hydrogen fuel cell design it can be very easy.
Hi. There are a lot of 3D softwares out there, you can try the students' versions of Autodesk softwares such as 3ds Max, Maya, Inventor or Autocad. Also Solidworks is a good idea. and if you want a free software, you can try Blender, there are multiple options.