New nano-structured and interactive supported composite electrocatalysts for hydrogen evolution with partially replaced platinum loading

Abstract

were studied by means of XRD, TEM, SEM and FTIR. The electrocatalytic activity was assessed in aqueous alkaline and polymer acidic electrolytes by means of steady-state galvanostatic method. It was found that Co strongly affects the platinum particle size. The addition of Co reduces platinum particle's size from 11 nm (in pure Pt metallic system) to 4 nm (in both systems 4:1 and 1:1), i.e. almost by 3 times. The corresponding increase of the surface area and the number of the active catalytic centres improves the efficiency, despite the fact that the amount of used platinum was decreased up to 5 times. The catalyst based on CoPt (1:1) performed the best, while the activity of the pure platinum and CoPt (4:1) systems were very close. Generally, the studied electrocatalysts have shown good and stable performances for hydrogen evolution in PEM electrochemical cell. The influence of the hydrogen electrodes under investigation on the water electrolysis efficiency at current density of 0.3 A cm À2 was assessed, using previous data oxygen evolution on IrO x electrode.Related to the performances of commercial Pt (ELAT) electrode, when hydrogen electrodes with the prepared mixed electrocatalysts were used, the water electrolysis efficiency was only 5% lower for CoPt (1:1), nearly 10% lower for CoPt (4:1) and 13% lower in the case of pure Co-based electrocatalyst.

Electrocatalytic activity of hypo–hyper-d-electrocatalysts (Me/TiO₂/MWCNTs) based on Co-Ru in alkaline hydrogen electrolyser

“…The amorphous character of Co in the corresponding electrocatalysts produced by the same procedure, and its particles of 2 nm were detected in the previous works of the present authors [13][14][15][16]. Also, it was detected that Pt particles in presence of Co showed consider-T a b l e 1 [19]. In the electrocatalyst with pure Pt as metallic phase, particle size of Pt were 12 nm, while in the electrocatalyst with mixed metallic phase CoPt (Co : Pt = 4 : 1, wt.…”

“…In this study, the size of Pt particles in electrocatalyst containing mixed metallic phase CoRuPt (Co : Ru : Pt = 4 : 0.5 : 0.5, wt., sample 3), are ≈2 nm. Due the higher Co : Pt ratio, the reduction of the Pt particle size is higher than in previous study [19]. The possibility that and Ru behaves as promoter for reduction of Pt particle size is not excluded.…”

“…But, the performance of these electrocatalysts in proton exchange membrane (PEM) electrolyser at lower cathodic overpotentials was poor due to instability of Co and Ni in acid medium, while at higher overpotentials their activity approaches the performance of a traditional Pt catalyst [18]. For this reason, further investigations were directed towards producing electrocatalysts with mixed metallic phase containing Co and Pt [19]. Cobalt behaves as a promoter of reducing Pt particle size during sol-gel synthesis of electrocatalysts.…”

Green nanotechnology of trends in future energy: a review

“…The process can be thermally reversed when the hydrogen is needed. For fastest release, other investigators are looking at compounds that “physi‐sorb” hydrogen: Instead of the hydrogen being chemically bound into a compound, hydrogen atoms or molecules are attracted by electrostatic or Van der Waals forces just to sit on the surface or inside molecular cages until released . In a word, fuel cells, reacted as hydrogen with oxygen to produce electricity, with the sole exhaust product being nonpolluting water are compact and very efficient in the future energy.…”

Integration studies on a two-stage fermentation process for the production of biohydrogen

“…Other processes under discussion involve electricity obtained from renewable resources to produce hydrogen through electrolysis of water. However, this kind of conversion implies efficiency losses between 30% and 50% (Paunovic et al, 2009).…”