Currently, the demand for energy is increasing so there is an interest in obtaining it from resources that do not generate greenhouse gases.The use of hydrogen as an energy vector is a clean and efficient alternative.This document provides a general approach to hydrogen as an alternative energy and methods for its generation, ranging from the use of fossil fuels to the use of water or organic matter.It should be noted that for this energy to be considered clean, the consumption of fossil fuels must be avoided.In this sense, the different clean technology processes are presented in a concise way, such as those carried out with photon energy, where photocatalytic methods and the challenges faced by the use of semiconductor materials in these processes are highlighted, as well as proposals to overcome them.Likewise, the use of nanostructured Bi2O3 as a semiconductor for the generation of hydrogen by photocatalytic water splitter is suggested since it allows taking advantage of the spectrum of sunlight and its properties depend on its crystalline structure.Also, the parameters that allow to improve its photocatalytic activity are shown.Finally, we conclude that the strategies presented here can be considered as the basis for the design of a photocatalytic material.