Porosity and thickness effect of Pd-Cu-Si metallic glasses on electrocatalytic hydrogen production and storage

Abstract

This contribution places emphasis on tuning pore architecture and film thickness of mesoporous Pd-Cu- Si thin films sputtered on Si/SiO2 substrates for enhanced electrocatalytic and hydrogen sorption/desorp-tion activity and their comparison with the state-of-the-art thin film electrocatalysts. Small Tafel slope of 43 mV dec-1 for 1250 nm thick coating on 2 gm diameter pores with 4.2 gm interspacing electrocatalyst with comparable hydrogen overpotentials to the literature suggests its use for standard fuel cells. The lar-gest hydrogen sorption has been attained for the 250 nm thick electrocatalyst on 5 gm pore diameter with 12 gm interspacing (2189 gC cm-2 per CV cycle), making it possible for rapid storage systems. Moreover, the charge transfer resistance described by an equivalent circuit model has an excellent cor-relation with Tafel slopes. Along with its very low Tafel slope of 42 mV dec-1 10 nm thick electrocatalyst on 2 gm diameter pores with 4.2 gm interspacing has the highest capacitive response of ti 0.001 S sn cm-2 and is promising to be used as a nano-charger and hydrogen sensor. The findings of Si/SiO2 supported mesoporous Pd-based metallic glass (MG) assemblies suggest a similar design applicability for crystalline systems and other MG types.