Steampunk Laughs Last: Hydrogen from Solar. reveals the unexpected origin of a new alternative energy technology – it isn’t new at all:

…[I]t may seem a bit out of place that, in 1833, an Italian physicist named G. D. Botto was performing experiments on a technique for generating hydrogen.

Botto’s original 19th-century device is quite simple. It consists of a chain of iron and platinum wires alternately connected as thermocouples, which are used to convert a temperature difference into an electric voltage. Botto then wrapped the chain around a wooden stick so that the iron-platinum junctions were evenly positioned on opposite sides of the stick. By heating the contraption with a flame of burning alcohol, Botto could generate an electromotive force. Further, by passing the generated electric current through water, he demonstrated how the method could be used to produce hydrogen through electrolysis.

“We think that this idea can be used in the production of hydrogen gas directly from solar energy, through electrolysis,” De Luca said. “However, nowadays, one would not use thermocouples, as in Botto’s experiment, but could, more efficiently, use thermoelectric semiconductors to obtain a much higher power output.”