Effect of acid functionalised carbon supports for Pd–Ni–Sn catalyst on ethanol oxidation reaction

Abstract

The sodium borohydride reduction method was employed to prepare a ternary catalyst with an atomic ratio of 20%Pd10%Ni10%Sn impregnated on four carbon supports, Vulcan XC-72R carbon black (CB), functionalised carbon black (CB sn ), multi-walled carbon nanotubes (MWCNTs) and functionalised MWCNTs (MWCNT sn ), to improve the catalytic activity for direct ethanol fuel cells (DEFCs). The acid functionalisation was performed using H 2 SO 4 and HNO 3 . The addition of Ni and Sn metals helped to increase catalytic activity as well as catalyst stability in the ethanol oxidation reaction (EOR). The XRD and XPS results confirmed the presence of Ni(OH) 2 and SnO 2 compounds. The crystalline size was in the range of 6.4 to 7.4 nm for all samples. TEM images of the catalyst on MWCNT sn confirmed that the catalyst particles were uniformly distributed and dispersed with a particle size in the range of 6 nm. This result was consistent with the highest number of active sites investigated by CO chemisorption. This was due to the highly crystalline structure of MWCNT sn . Moreover, the catalyst on MWCNTs exhibited the highest current density (291 mA cm À2 ) for EOR, great catalyst stability, the highest electrochemical surface area (77.155 m 2 g À1 Pd) and excellent CO tolerance.

Superior electrocatalytic activity of ultrathin PtPdBi nanowires towards ethanol electrooxidation

“…2A and B. As expected according to the ECSA values, Pt 55 Pd 38 Bi 7 /C shows the best catalytic activity ($2.30 A mg À1 ) among three Pt x Pd 93Àx Bi 7 /C samples, slightly better than PdNiSn/C (2.15 A mg À1 ), 43 and $2 times better than the commercial Pt/C ($1.20 A mg À1 ). Two well-dened oxidation peaks were clearly observed in Fig.…”

Synthesis and Characterization of PdAgNi/C Trimetallic Nanoparticles for Ethanol Electrooxidation

“…Moreover, it would modify the Pd geometry and electronic configuration and tune in its adsorption characteristics. Ni has been proven a beneficial cocatalyst when added to Pd because it can generate OH at a lower applied potential and modify the electronic structure of Pd [ 22 , 23 , 24 , 25 , 26 , 27 ]. The coexistence of Ni and Ni(OH) 2 can enhance alcohol oxidation on transition metals in acidic and basic electrolytes [ 6 , 28 ].…”

The Role of a Sn Promoter on an Anodic Pt Electrocatalyst Prepared over H2O2‐Functionalized Carbon Supports for Direct Ethanol Fuel Cell (DEFC) Applications

“…Some authors [50,62–64] have reported the existence of diffusion restrictions in carbon micropores after other different chemical treatments. Therefore, the reduction of the surface area after H 2 O 2 functionalization could be caused by the blockage of part of the micropores.…”

“…As it is observed, the surface area value for CNT and VC supports decreases after functionalization treatment by approximately 24 and 32 %, respectively. Some authors [50,[62][63][64] have reported the existence of diffusion restrictions in carbon micropores after other different chemical treatments. Therefore, the reduction of the surface area after H 2 O 2 functionalization could be caused by the blockage of part of the micropores.…”