Challenges for hydrogen production from hydrocarbons and renewable sources

This paper begins with a discussion on the global energy challenges and the needs for clean and more efficient energy development, followed by the challenges for hydrogen energy research with a focus on the chemical processing options for hydrogen production in conjunction with hydrogen utilization in fuel cells and chemical processing, energy efficiency improvement, and mitigation of CO2 emissions. Molecular hydrogen is an energy carrier but not a primary energy resource. Thus H2 molecules must be produced using hydrogen atom sources with energy input. Hydrogen energy does not play a major role in changing the primary energy supply or energy sources, as it is a secondary energy like electrical energy. By atomic hydrogen and energy sources, hydrogen can be produced from coal (gasification, dehydrogenation, carbonization), natural gas and propane gas (steam reforming, partial oxidation, autothermal reforming, plasma reforming, dehydrogenation or decomposition), petroleum fractions (dehydrocyclization and aromatization, oxidative steam reforming, pyrolytic decomposition), biomass (gasification, steam reforming, biological conversion), and water (electrolysis, photocatalytic conversion, chemical and catalytic conversion). There are major challenges in each of these paths and thus there exist major opportunities for advances in the field.