Depth Filtration and Pre-Treatment Solutions for Fuel Cell Feed Streams: A Comprehensive Review of Mechanisms, Materials, and Emerging Technologies

Abstract

PEMFCs and other electrochemical energy conversion devices require exceptionally clean feed streams - specifically clean hydrogen (H 2 ) and air without particulate matter, chemical contaminants, sulfur compounds, carbon monoxide, ammonia, and biological agents. Poisoning of catalysts: potentia| The level of feed stream impurities, even on a part-per-billion (ppb) level, may lead to irreversible catalyst poisoning, degradation of the membrane and disastrous performance losses. Multi-mechanism separation strategy depth filtration has become one of the foundations as a pre-treatment technology that combines both particle capture, adsorption and electrostatic retention in a three-dimensional porous network. This is a comprehensive review that methodically analyzes (i) the main mechanisms of depth filtration and related pre-treatment processes, (ii) novel materials (e.g., fibrous, granular, ceramic, and nanostructured adsorbents) used in fuel cell conditioning systems, (iii) key pollutants and their critical permissibility levels, (iv) multi-stage pre-treatment train integration, The quantitative performance comparisons based on peer-reviewed literature are combined into adherent tables and schematic figures. The review also reveals existing obstacles and prospects of scalability of the future research as key to commercializing the next-generation fuel cell systems in automotive, stationary, and portable applications.