It's one of many, many research projects in thermochemical hydrogen production -- the idea of splitting water using only heat (thermal decomposition), indirectly through longer chemical processes. It's been going on since at least 1977 [1], and there's 352 known thermochemical cycles for splitting water [2] (including zinc/zinc oxide), including the 14 listed [2] on wikipedia. The news today is that a grad student in Delaware built a small lab version of one of these, which he plans to run experiments with. His school media office wrote a press release for him [3], which was cloned by Physorg and written about on a few blogs.

In general, the idea (thermochemical hydrogen production) is just what you say -- heat in (solar, nuclear also researched), hydrogen out. No byproducts, as the chemical intermediates form a closed cycle.

[1] http://www.osti.gov/energycitations/product.biblio.jsp?osti_...

[2] http://en.wikipedia.org/wiki/Water_splitting

[3] http://www.udel.edu/udaily/2012/apr/solar-reactor-040312.htm...