Sustainable Hydrogen and Ammonia Technologies with Nonthermal Plasma Catalysis: Mechanistic Insights and Technoeconomic Analysis

The search for novel catalytic processes is essential to combat climate change by tapping into sustainable hydrogen technologies, which rely on low-carbon H2 production and efficient H2 storage for global transportation. Ammonia, which can function as a H2 carrier for later dehydrogenation in COx-free hydrogen production, is recognized as one of the key solutions. The utilization of nonthermal plasma to catalyze reactions is a plausible means of replacing CO2-polluting fossil-dependent thermal processes. In this perspective, we summarize currently explored mechanistic insights in the catalytic plasma reactions to evaluate their readiness for industrial applications and propose future research outlooks in plasma-driven hydrogen technologies, with a primary focus on ammonia reactions. Relevant reaction mechanisms and catalytic design in other reaction systems that involve hydrogen storage (e.g., CO2 hydrogenation, CO2 methanation) and hydrogen production (e.g., methane reforming) are also evaluated to supplement our primary discussion on ammonia synthesis and decomposition. We further discuss possible implications of using plasma catalysis from the perspective of energy efficiency in comparison to existing thermal-catalytic counterparts, wherein we include insights obtained from different reaction systems, catalyst design innovations, and reactor engineering. Herein, we present current research gaps and propose future research directions to achieve energy-efficient catalytic plasma hydrogen technologies.