Polysilanes, inks containing the same, and methods for their preparation are disclosed. The pump comprises a first pump inlet 120 through which fluid can enter the pump and pass through both the first and second pumping sections towards a pump outlet, and a second pump inlet 122 through which fluid can enter the pump and pass through only the second pumping section towards the outlet. The surface nanostructure comprises catalyst nanoparticles made of platinum and carbon nanoparticles.