ABSTRACT

Ever since its discovery, hydrogen has been a source of fascination for the scientific community. As early as the sixteenth century, scholars reported a gas evolution reaction resulting from adding metal to acidic solutions. In 1766, Henry Cavendish recognized that the evolved gas was in fact hydrogen (Cavendish 1766; Al-Khalili 2010). Hydrogen is, after all, the most common element in the universe (Palmer 1997) and is responsible for the majority of the mass-to-energy conversion happening in the stars. It also forms the simplest atomic entity H, a combination of a single proton and a single electron, the simplest example of multi-atomic molecule H2, the simplest of all ionic species H+, and, of interest to electrochemists worldwide, presents the simplest electrochemical reaction

2 2 2H e H + + « (5.1)

On a (much) smaller scale, our planetary scale, it can also be a foundation of the carbon-free energy conversion scheme, the so-called “hydrogen economy,” a term coined and a concept formed in the early seventies by one of electrochemistry’s greatest minds, Dr. Bernhardt Patrick John O’Mara Bockris (Bockris and Appleby 1972), a big proponent of a global conversion from carbon-based energy carriers to the hydrogen-based ones.* Bockris’ dreams of hydrogen economy were perhaps well ahead of their time in the seventies and were not getting much of the traction back then. Today, however, the situation seems to be changing dramatically, and the vision of hydrogen economy may not be such a pipe dream anymore.