Nanostructured Pd-Based Electrocatalyst and Membrane Electrode Assembly Behavior in a Passive Direct Glycerol Fuel Cell

Abstract

The aim of this study was to synthesize, characterize, and observe the catalytic activity of Pd 1 Au 1 supported by vapor-grown carbon nanofiber (VGCNF) anode catalyst prepared via the chemical reduction method. The formation of the single-phase compounds was confirmed by X-ray diffraction (XRD) and Rietveld refinement analysis, which showed single peaks corresponding to the (111) plane of the cubic crystal structure. Further analysis was carried out by field emission scanning emission microscopy (FESEM), energy dispersive X-ray analysis (EDX), nitrogen adsorption/desorption measurements, and X-ray photoelectron spectroscopy (XPS). The electrochemical performance was examined by cyclic voltammetry tests. The presence of mesoporous VGCNF as support enables the use of a relatively small amount of metal catalyst that still produces an excellent current density (66.33 mA cm −2 ). Furthermore, the assessment of the kinetic activity of the nanocatalyst using the Tafel plot suggests that Pd 1 Au 1 /VGCNF exerts a strong electrocatalytic effect in glycerol oxidation reactions. The engineering challenges are apparent from the fact that the application of the homemade anode catalyst to the passive direct glycerol fuel cell shows the power density of only 3.9 mW cm −2 . To understand the low performance, FESEM observation of the membrane electrode assembly (MEA) was carried out, examining several morphological defects that play a crucial role and affect the performance of the direct glycerol fuel cell.

An Overview of Glycerol Electrooxidation Mechanisms on Pt, Pd and Au

“…According to many GEOR studies, Pd has a much higher d‐band center and lower catalytic activity compared to Pt [32] . Also, it is observed that the catalytic activity of Pd is much inferior to Pt without base‐catalyzed deprotonations [142] . In addition, from cyclic voltammetry under alkaline condition, the onset potential of observable GEOR is very close to the formation of OH(ads) (e. g. within 100 mV; see Table 1).…”

“…The partial deprotonation at a primary carbon produces glyceraldehyde and deprotonation at the secondary carbon leads to DHA [33] . In addition, complete deprotonation at a primary carbon generates CH 2 OHCHOHCO(ads), [142] which is an intermediate leading to C−C bond cleavage. This cleavage is shown by the production of CO(ads) in acidic conditions and the subsequent evolution of CO 2 .…”

“…In addition, the lattice strain generated by ad‐atoms can also downshift the d‐band center of the metal they modify, and the effectiveness of lattice strain depends on the difference between their lattice parameters [162] . This downshift would cause the back‐donation of electrons from Pt (5d) to CO(ads) (2p*), which reduces the bond strength of M−CO and promotes the CO removal [2,142] . It is also reported that the position of the d‐band center (associated with the binding energy of intermediates) can be modulated by the morphology and shape of metallic nanoparticles [163] .…”

Research and innovation in the electrocatalyst development toward glycerol oxidation reaction

“…Xu et al 40 making a metal content ratio of 1:1, and comparing to other groups; the catalyst exhibited S C H E M E 3 Linear sweep curves of Pt (left) and Pd electrode in alkaline media 31 [Colour figure can be viewed at wileyonlinelibrary.com] unique one-dimension nanowires (1D NWs) structure due to the optimum ratio of dual capping agents, polyvidone (PVP), and C 19 H 42 BrN (CTAB). Pd-Au NWs were able to produce high mass activities for a short time, but Pt-Au NWs could retain higher mass activities for a longterm period due to better durability.Lam et al, 41 Ottoni et al, 42 Cai et al, 43 Rezaei et al, 44 Dong et al, 45 and Yahya et al 46,47 researched various molar ratios for Pd/Au catalyst. Lam et al 41 reported Pd-Au bi-functional mechanism caused oxidation removal of residual intermediate poisons on active Pd surface to enable GOR to restart.…”

Synthesis, Characterization and Potential of Pt-Ru Supported Carbon Nanocage (CNC) Electrocatalystfor Future DMFC

“…However, the SBET decreased after dispersed of catalyst metal on CNC support but, the SBET of Pt-Ru/CNC electrocatalyst still showed higher value than Pt-Ru/C. The decreased of BET specific surface area of Pt-Ru/CNC after dispersion of Pt-Ru metals on CNC support indicates that the catalyst metal was successfully deposited onto the surface of CNC support [42,49]. This is also due to the present of Pt-Ru catalyst particles onto the CNC support that blocks some micropores which then leads to the decreased of BET specific surface area [35].…”