Hydrogen is clean and renewable, and recognized as a very promising energy resource to solve both
depletion of petroleum and environmental problems caused by the use of fossil fuels. Extensive researches
have been performed worldwide on the production technologies of hydrogen. In this paper, the technology
trend of photo-electrochemical (PEC) hydrogen production was scrutinized based on the patent and paper
analysis. Open/registered patents of US, JP, EP, and KR and SCI Journals related to the PEC hydrogen
production technology between 1996~2010 were reviewed. Patents and papers were gathered by using the
key-words searching method and filtered by desirable filtering criteria. The technology trend was discussed
by classifying each patent and paper based on the publishing year, country, and organization, and analyzing
the core patents and papers.