Ordered Intermetallic Nanostructured PtSb/C for Production of Energy and Chemicals

Abstract

This paper has evaluated ordered intermetallic nanostructured PtSb/C as anode for glycerol electrochemical oxidation in both acidic and alkaline media. Nanostructured PtSb/C performed as well as and 50 % better than commercially available Pt/C nanoparticles in acidic and basic media, respectively. The presence of Sb atoms in the material structure enhanced C-C bond cleavage activation in alkaline medium. Spectroelectrochemical studies confirmed that the reactions conducted in acidic and alkaline solutions produced high-value chemicals. Depending on the nature of the employed electrolyte, the nanostructured PtSb/C material can potentially afford interesting compounds for the chemical industry or even generate electrical energy.

Electrochemical Energy Conversion on Intermetallic Compounds: A Review

“…PtSb (NiAs type of crystal structure) nanoparticles, synthesized via the polyol route and the additional reducing agent NaBH 4 , were applied for the electrooxidation of glycerol, showing comparable activity to Pt/C in acidic but enhanced performance in alkaline media. In the latter, an improved C–C bond cleavage is observed by means of spectro-electrochemical results, indicating a positive effect of Sb on Pt, most likely due to electron transfer . It is also likely that Sb is providing activated OH* species via a spillover mechanism, as the catalyst already contains Sb 2 O 5 , which may serve as OH* storage, as proposed by Jaksic et al …”

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

“…In the last decade, this method has been applied to the identification of the adsorbates and intermediates during GEOR. So far, many peaks/bands of IR spectra have been assigned to specific vibrational modes [50,124] . Nevertheless, controversies of peak identification still exist as the convolution of peaks may mask weak bands or shift the center of peaks.…”

“…Sb and Bi tend to oxidize the secondary hydroxy groups (via chelating and blocking effects as shown in Figure 13, as Bi chelates with secondary alcohol groups), while Pb and In promote the primary alcohol oxidation [53] . Sb is believed to facilitate C−C bond breakage at Pt under alkaline condition, [124] while others discovered an inhibiting effect in an acidic solution [158] . Whether Sn can promote the dissociation of C−C bonds with Pt catalysts is still under debate [176,177] …”

“…Reducing the number of these ensembles lowers the efficiency of primary alcohol conversion, whereas secondary alcohol conversion is not affected as it only requires one Pt/Pd atom [39] . Benefitting from that, high selectivity towards DHA (partially converted to glyceraldehyde via isomerization [124] and further to glycerate if in strong alkali [121] ) through the preferential oxidation of the secondary carbon can be achieved, as exemplified by Bi‐modified, [54] Ru‐modified, [146] and Sb‐modified Pt [14,53] . Moreover, researchers have reported that Sb has a remarkably higher selectivity towards DHA (61.4 %, obtained at 0.797 V vs RHE) than Bi (usually between 10–20 %) and a higher potential of oxidation towards its oxide [49] …”

Research and innovation in the electrocatalyst development toward glycerol oxidation reaction

“…159 The Sb element is expected to adsorb hydroxyl molecules much better than noble metal and can provide electronic, steric, and bifunctional effects. 160 Scachetti et al 161 synthesized Pt-Sb/C in which the Sb is another oxophilic that favored oxide formation on the catalyst surface. The Sb element promoted glycerol dissociative adsorption with C C bond cleavage in the hydrogen region.…”