The present utility model relates to a catalyst layer for proton exchange membrane fuel cells (PEMFCs). The catalyst layer comprises a carbon support film formed from biochar derived from water hyacinth (Eichhornia crassipes), a platinum catalyst integrated into the carbon support film, and a polymeric binder.  The integration of platinum into the biochar-based carbon support provides a uniform and stable catalytic film with enhanced electrochemical activity. The catalyst layer is further
characterized by its self-supporting structure, uniform morphology, and durability under oxidative and thermal conditions, making it suitable for PEMFC applications.