✔ 最佳答案
Water is the richest source of hydrogen. If we can use the hydrogen from water as a fuel, it will be perfect. Practically, by eectrolysis, we can get the hydrogen easily from water. However, this method change one the chemical energy from one form to another form. In fact, this conversion is a waste of energy since there is always a waste of enrgy during energy transfer according to the thermodynamics rules. The most effective method is to utilize the solar energy to split the hydrogen and oxygen from the water. In this case, we are converting the solar energy into the chemical energy. The principle is just like what the plant doing in photosynthesis in which the carbon is fixed in the form of carnobhydrate to provide energy to the living organisms. In fact, a lot of researchs have been done but none of them has been practically use in our daily life.