With global resource shortage and deterioration of ecological environment, the research and development of clean and renewable energy is of vital importance. Using first principles calculations, we firstly study water splitting catalyzed by metal based biomolecule porphyrin (MPP) (M = Mg, Ba, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn). Among all the systems, after releasing electron, TiPP is the most effective catalyst for H2O splitting. TiPP and the remainder O atom form the very stable structure OTiPP. The H-2-O + OTiPP can release electron with the 6.76 eV potential barrier. The releasing electron process of porphyrin can be easily realized under the effect of solar energy by experiment study. After releasing electron, OTiPP can effectively catalyze the dissociation of H+ from H2O in an exothermic process. The desorption of O atom is an endothermic process with 0.72 eV barrier. The H2O + OTiPP system can readily return to its original state OTiPP, in other word, the OTiPP can be a sustainable cycling catalyst for water splitting under the effect of potential barrier transfer. The whole catalytic process is remarkable clean without any pollution. This method may open up new avenues for the development of future clean energy and extraordinary biomimetic photosynthesizers. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.