Benzene in hydrogen fuel: Effects on PEMFC performance and relevance to fuel quality standards

With a system simulating the operation of automotive type proton exchange membrane fuel cells (PEMFCs), this study examines the impact of benzene impurity on PEMFCs. A 10-cell stack was operated at 0.6 A cm −2 with anode gas recirculation and intermittent purging. Benzene concentrations of 11, 23, and 45 ppm were introduced, alone and with 1 ppm CO. At 99.5% fuel utilization, contaminant enrichment was 200-fold in the recirculation loop. Results show negligible impact of benzene on PEMFC performance, even at 45 ppm. Gas analysis confirmed complete hydrogenation of benzene to cyclohexane, with >1% cyclohexane detected in the anode recirculation. These findings suggest benzene should be regulated separately from the total hydrocarbon limit in ISO 14687. Relaxed limits would reduce costs for hydrogen transport and storage, supporting liquid organic hydrogen carriers, repurposed pipelines, and geological storage, thereby enabling broader deployment of cost-effective hydrogen supply chains. • At fuel utilization ≥99.5%, 45 ppm benzene does not impair PEMFC performance. • Anode gas shows benzene hydrogenation to cyclohexane during operation. • Data supports setting explicit ISO 14687 limits for aromatic hydrocarbons. • Relaxing benzene limit could facilitate LOHC-based hydrogen supply chains.