About the Technological Readiness of the H-2 Generation by Hydrolysis of B(-N)-H Compounds

At the beginning of the new millennium, hydrolysis of sodium borohydride (NaBH4) was presented as a promising on-board technology to generate H-2 for light-duty vehicles. Years later, other B(-N)-H compounds (e.g., lithium borohydride (LiBH4) and ammonia borane (NH3BH3)) emerged as attractive alternatives whereas NaBH4 was struggling with several issues jeopardizing its implementation. Actually, efforts in the research and development of H-2 generation by hydrolysis of B(-N)-H compounds have been intensive since the advent of NaBH4 almost 20 years ago. There may be a question with respect to this: What is the technological readiness of the promising hydrolytic B(-N)-H compounds? This Review aims at providing relevant elements in response to this question. In the first part, the most mature B(-N)-H compounds are discussed at length. In the second part, a survey of all other candidates is proposed. It is concluded that NaBH4 is the best hydrolytic B(-N)-H compound for marketing on a broad scale, but there are still key challenges to address.