Towards a more sustainable future: Transitioning from thermochemical to electrochemical processes in clean energy technologies relevant to hydrogen-containing fuels

Abstract

This review paper explores the transition from thermochemical to electrochemical processes in clean energy technologies, particularly focusing on hydrogen-containing fuels, namely hydrogen, ammonia, and methanol. The main characteristics of the thermochemical and electrochemical technologies are compared, followed by a focus on specific approaches in production of each of these e-fuels. Steam methane reforming, partial oxidation of hydrocarbons, coal and biomass gasification, as well as thermal decomposition and autothermal reforming processes are discussed for hydrogen thermochemical production. Electrochemical technologies for green hydrogen production are then described, including water electrolysis based on alkaline, proton exchange membrane, anion exchange, and solid oxide cells. The paper further compares the Haber–Bosch process with the electrochemical synthesis of ammonia, and discusses thermochemical technologies for methanol synthesis from syngas, comparing them to the two electrochemical approaches-electrochemical CO₂ reduction and methane oxidation reaction. Additionally, approaches for extracting hydrogen from ammonia and methanol by electrochemical reforming are briefly discussed. The paper closes with the future prospects and challenges of the transition from the traditional thermochemical technologies to the more sustainable electrochemical processes. Despite the promising prospects of the electrochemical technologies, challenges such as high initial capital costs, the need for advanced materials, and scalability must be addressed. Ongoing research, policy incentives, and collaborative efforts are essential to overcome these barriers and facilitate the transition to a low-carbon economy. In the meantime, the integration of these technologies represents a transformative approach to chemical manufacturing and energy management, offering a pathway towards more sustainable and versatile industrial practices.