Overall water splitting: What’s next?

Photocatalytic overall water splitting reaction driven by sunlight has been studied as a means of producing renewable solar hydrogen on a large scale. The practicality of this technology will ultimately depend on the cost of the produced solar hydrogen. This cost, in turn, is determined by various factors such as solar-to-hydrogen energy conversion efficiency, scalability, construction/operating costs and the service life of such systems. This article both summarizes the current state of development of photocatalytic overall water splitting technology and presents issues that must be addressed in the future to allow such systems to have real-world utility.