Gas diffusion electrodes based on carbon and graphene for pem fuel cell
Yarar Kaplan, Begüm (2017) Gas diffusion electrodes based on carbon and graphene for pem fuel cell. [Thesis]
All the components of gas diffusion electrodes (GDE) of PEM fuel cells were developed in this thesis. In the first part, new carbon and cellulose fiber-based composite gas diffusion layer (GDL) were developed for PEM fuel cell by using a green and environmentally friendly 'wet-laying’ process and electrically conducting composite GDLs with excellent flexibility, uniformity, and porosity were achieved. Moreover, PEM fuel cell performance of the fabricated composite GDL was investigated. It was determined that these GDLs exhibited similar power output especially at low temperature compared to commercial carbon paper. In second part of the thesis, novel electrocatalysts comprising Pt nanoparticles impregnated on reduced graphene oxide (rGO) and carbon black (CB) hybrid carbon supports with varying ratios were developed by using rapid one-pot microwave irradiation. CB was used as an intercalating agent to avoid restacking of rGO sheets. Pt/rGO-CB hybrid electrocatalyst with low CB content (25% wt.) delivered superior electrocatalytic activity and fuel cell performance and power output (max. power density 1091 mW cm-2) compared to those of Pt/CB and Pt/rGO with 0.4 mgPt/cm2 loading. In third part of the thesis, a novel catalyst layer (CL)containing Pt/graphene and Pt/graphene-CB hybrids by electrospraying for PEM fuel cells were developed. Electrosprayed CL provided uniform and small size Pt distribution, and with introducing graphene-CB hybrids highly conductive and porous catalyst layer was achieved. Compared to conventional air-sprayed CL, electrospayed CL was showed better PEM fuel cell performance with the max. power densities of 441 mW cm-2 for electrosprayed electrode, and 327 mW cm-2 for air- sprayed electrode, were obtained at a relatively low Pt loading (0.2 mgPt/cm2).
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