The present utility model concerns a catalyst support layer for proton exchange membrane fuel cells (PEMFCs), comprising a carbon film made from biochar derived from water hyacinth (Eichhornia crassipes), uniformly blended with polyvinylidene fluoride (PVDF) binder at a 50:50 weight ratio. The carbon film demonstrates suitable morphological and surface characteristics, including hydrophobicity and disordered carbon structure, which render it effective as a catalyst support layer in PEMFC applications. This catalyst support layer offers a sustainable and cost-effective alternative to commercial carbon supports by utilizing invasive biomass waste.