A comparative study on carbon neutral hydrogen carrier production: Formic acid from CO2 vs. ammonia

Hydrogen (H2) is increasingly recognized as a key player in the journey towards carbon neutrality, with ammonia (NH3) and formic acid (FA) emerging as significant hydrogen vectors. This review highlights advancements in catalyst efficiency for FA synthesis from CO2, particularly with bismuth (Bi) and tin (Sn) catalysts. It investigates diverse NH3 and FA production methodologies, such as electrochemical, thermochemical, and photochemical processes, and underscores the integration of renewables to address their energy demands. The study also reviews novel materials like metal-organic frameworks (MOFs) and carbon-based catalysts that could enhance catalytic effectiveness. Transitioning from lab-scale models to industrial-scale applications requires addressing catalyst longevity and process enhancement, and it suggests investigating hybrid systems that might offer improved efficiency and yields. Concluding with a directive for future research, the study advocates for scalable, economically viable, and environmentally sustainable CO2 conversion technologies, underscoring the essential roles of NH3 and FA in a future with reduced carbon emissions.