Adsorption of phosphate species on poly-oriented Pt and Pt(1 1 1) electrodes over a wide range of pH

Third-body effects of native surfactants on Pt nanoparticle electrocatalysts in proton exchange fuel cells

The third-body effect of oleylamine could enhance the oxygen reduction reaction of Pt nanoparticles in the presence of specifically adsorbed anions despite the quite small electrochemical surface active area.

Platinum nanoparticles functionalized with ethynylphenylboronic acid derivatives: selective manipulation of nanoparticle photoluminescence by fluoride ions

Platinum nanoparticles functionalized with 4-ethynylphenylboronic acid pinacol ester (Pt-EPBAPE) were successfully synthesized by a simple chemical reduction procedure. Because of the formation of conjugated metal-ligand interfacial linkages, the resulting nanoparticles exhibited apparent photoluminescence arising from the nanoparticle-bound acetylene moieties that behaved analogously to diacetylene derivatives. Interestingly, the nanoparticle photoluminescence was markedly quenched upon the addition of fluoride ions (F⁻). In contrast, significantly less or virtually no change was observed with a variety of other anions such as Cl⁻, Br⁻, I⁻, NO₃⁻, HSO₄⁻, H₂PO₄⁻, ClO₄⁻, BF₄⁻, and PF₆⁻. The high selectivity toward fluoride ion is most probably because of the strong specific affinity of the boronic acid moiety to fluoride. The formation of B-F bonds led to the conversion of Bsp² to Bsp³, as manifested in ¹¹B NMR measurements, which impacted the intraparticle charge delocalization between the particle-bound acetylene moieties and hence the nanoparticle photoluminescence.

pH dependence of the electroreduction of nitrate on Rh and Pt polycrystalline electrodes

From a study of the electrocatalytic reduction of nitrate on Pt and Rh electrodes over a wide pH range, HNO₃ is suggested as the only reducible species in nitrate reduction on Pt, whereas both HNO₃ and the nitrate anion are reducible on Rh.

Tailoring the Electronic Structure of Nanoelectrocatalysts Induced by a Surface-Capping Organic Molecule for the Oxygen Reduction Reaction

Capping organic molecules, including oleylamine, strongly adsorbed onto Pt nanoparticles during preparation steps are considered undesirable species for the oxygen reduction reaction due to decreasing electrochemical active sites. However, we found that a small amount of oleylamine modified platinum nanoparticles showed significant enhancement of the electrochemical activity of the oxygen reduction reaction, even with the loss of the electrochemically active surface area. The enhancement was correlated with the downshift of the frontier d-band structure of platinum and the retardation of competitively adsorbed species. These results suggest that a capping organic molecule modified electrode can be a strategy to design an advanced electrocatalyst by modification of electronic structures.

Sorption of phosphate onto giant reed based adsorbent: FTIR, Raman spectrum analysis and dynamic sorption/desorption properties in filter bed

A sorption process for the removal of phosphate was evaluated under various conditions using a filter bed packed with giant reed (GR) based adsorbent. FTIR spectrum measurement validated the existence of grafted amine groups in the adsorbent and Raman spectrum displayed the characteristic peaks of different forms of phosphate. The column sorption capacity of the adsorbent for phosphate was 54.67 mg g(-1) in comparison with the raw GR of 0.863 mg g(-1). Influent pH demonstrated an essential effect on the performance of the filter bed as compared to other influent conditions (flow rates and influent concentrations) and the optimal pH was selected at 5.0-10.0. Eluents of HCl, NaOH and NaCl solutions with concentrations of 0.01-0.1 mol l(-1) showed the excellent capacities for desorption of phosphate from the adsorbent, and their elution processes could be finished in 90 min.