Doğrudan Sodyum Borhidrürlü Yakıt Pili Anot ve Katot Elekrokatalizörünün Sentezi ve Karakterizasyonu

Abstract

In this study, cathode and anode electrocatalysts of direct sodium borohydride fuel cell were produced by both precipitation and spray pyrolysis methods. The purpose of this study is the optimization of the catalyst production parameters and to develop multivariate models involving production parameters which depend on power density, hydrogen production rate, catalyst production cost and energy cost for gram catalyst. In the first section, seven different Pt based catalysts were synthesized by precipitation method and they were compared in terms of high power density and minimum hydrogen production rates. Using a fuel cell with an effective area of 25 cm2 , these seven catalysts were investigated and it was found that PtAu/C gave the highest power density and the lowest hydrogen production rate. In the second section, the production parameters were investigated for precipitation methods for the chosen PtAu/C catalyst. The synthesized electrocatalysts were characterized by physical (XRD, TEM, BET) and chemical (cyclic voltametry) methods and performance analyses were carried out by single cell tests. Preparation parameters were optimised by using Surface Response Method where preparation temperature, pH of the system, drying time and % Au metal ratio (weight of Au metal/weight of total metal) were selected as independent process parameters. Effects (responses) on dependent parameters of power density, hydrogen production rate, catalyst production cost, cost for 1 W power and power per gram catalyst were investigated using surface response methodology. The solution of the optimization program Design Expert yielded the optimum conditions for maximum power density and minimum hydrogen production rate (by disregarding production cost).