Bismuth modified Pd/C as catalysts for hydrogen related reactions

Alkaline Ethanol Oxidation Reaction on Carbon Supported Ternary PdNiBi Nanocatalyst using Modified Instant Reduction Synthesis Method

Direct ethanol fuel cells (DEFC) still lack active and efficient electrocatalysts for the alkaline ethanol oxidation reaction (EOR). In this work, a new instant reduction synthesis method was developed to prepare carbon supported ternary PdNiBi nanocatalysts with improved EOR activity. Synthesized catalysts were characterized with a variety of structural and compositional analysis techniques in order to correlate their morphology and surface chemistry with electrochemical performance. The modified instant reduction synthesis results in well-dispersed, spherical Pd₈₅Ni₁₀Bi₅ nanoparticles on Vulcan XC72R support (Pd₈₅Ni₁₀Bi₅/C^(II-III)), with sizes ranging from 3.7 ± 0.8 to 4.7 ± 0.7 nm. On the other hand, the common instant reduction synthesis method leads to significantly agglomerated nanoparticles (Pd₈₅Ni₁₀Bi₅/C^(I)). EOR activity and stability of these three different carbon supported PdNiBi anode catalysts with a nominal atomic ratio of 85:10:5 were probed via cyclic voltammetry and chronoamperometry using the rotating disk electrode method. Pd₈₅Ni₁₀Bi₅/C^(II) showed the highest electrocatalytic activity (150 mA⋅cm⁻²; 2678 mA⋅mg⁻¹) with low onset potential (0.207 V) for EOR in alkaline medium, as compared to a commercial Pd/C and to the other synthesized ternary nanocatalysts Pd₈₅Ni₁₀Bi₅/C^(I) and Pd₈₅Ni₁₀Bi₅/C^(III). This new synthesis approach provides a new avenue to developing efficient, carbon supported ternary nanocatalysts for future energy conversion devices.

Graphical Abstract

Size control and catalytic activity of highly dispersed Pd nanoparticles supported on porous glass beads

This paper presents a novel in situ method to prepare monodispersed palladium nanoparticles supported on porous glass beads with an egg-shell structure at room temperature. This method integrates two processes of ion exchange and reduction in one step just by changing the solvent from water to alcohol. The monodispersed Pd nanoparticles around 3.75 nm in diameter with a face-centered cubic structure have been successfully prepared. The adsorption capacity for palladium reached 55.00 ± 0.55 mg/g in ethanol, which was 26 times larger than that in water. These Pd nanoparticles supported on porous glass beads showed an excellent catalytic performance through the hydrogenation of cyclohexene. In addition, this in situ method was also successfully applied to prepare monodispersed silver and gold nanoparticles supported on porous glass beads. Overall, this facile method provided an alternative for preparing a supported nanoparticle catalyst in a green way.