Novel Hybrid Catalyst for the Oxidation of Organic Acids: Pd Nanoparticles Supported on Mn‐N‐3D‐Graphene Nanosheets

Abstract

This paper reports the fabrication and electrochemical performance of a hybrid catalyst composed of Pd nanoparticles and atomically dispersed Mn active centers integrated into the nitrogen‐doped three‐dimensional graphene nanosheets (Pd/Mn−N‐3D‐GNS). Our results show that the synergistic integration of both Pd nanoparticles and atomically dispersed Mn can be used to enhance the activity toward the electrochemical oxidation of organic acids at biologically relevant pH values. The hybrid catalyst (Pd/Mn−N‐3D‐GNS) showed increased maximum currents toward the oxidation of oxalic acid when compared to its individual catalysts, namely, Pd/3D‐GNS and Mn−N‐3D‐GNS catalysts. The hybrid also showed a decreased onset potential for oxidation of mesoxalic acid as compared to Mn−N‐3D‐GNS and decreased onset potentials for the oxidation of glyoxalic acid when compared to both of its constituent catalysts. Oxidation of formic acid was also tested and the hybrid was shown to catalyze both dehydration and dehydrogenation mechanisms of formic acid electro‐oxidation. Using density functional theory calculations, it was elucidated that a two‐site catalysis most likely promotes dehydrogenation reaction for formic acid oxidation, which can explain the selectivity of Pd nanoparticles and atomically dispersed Mn towards the dehydrogenation/dehydration pathway.

Role of Nitrogen Moieties in N-Doped 3D-Graphene Nanosheets for Oxygen Electroreduction in Acidic and Alkaline Media

“…However, in any case, none of the nitrogen moieties seemed to be catalyzing the direct 4e – reduction of oxygen, in neither acidic (O 2 + 4e – + 4H + → H 2 O) nor alkaline media (O 2 + 2H 2 O + 4e – → 4OH – ). Hence, nitrogen-doped graphene materials, especially ones with a high abundance of hydrogenated-N moieties, would do best when utilized as a support for nanoparticles, such as Pt, Pd, , or other transition metal-functionalized electrocatalysts. , …”

“…Hence, nitrogen-doped graphene materials, especially ones with a high abundance of hydrogenated-N moieties, would do best when utilized as a support for nanoparticles, such as Pt, Pd, 61,62 or other transition metal-functionalized electrocatalysts. 63,64…”

Nitrogen-Doped Three-Dimensional Graphene-Supported Palladium Nanocomposites: High-Performance Cathode Catalysts for Oxygen Reduction Reactions

“…Figure c­(ii) shows the TEM image of Pd nanoparticles on N/3D-GNS supports deposited using the previously established surfactant-free SARM. This method was shown to consistently deposit Pd nanoparticles with an average diameter of 5 nm uniformly dispersed on the surface. , Figure a shows the X-ray diffraction patterns recorded for the 3D-GNS support (Figure ai) and palladium nanoparticles deposited on the N/3D-GNS supports. The shift and increased intensity of the peak corresponding to graphitic carbon (*) at 26.3° (Figure aii) indicates the increased graphitization of the N/3D-GNS supports following the additional NH 3 pyrolysis at 850 °C.…”

“…This method was shown to consistently deposit Pd nanoparticles with an average diameter of 5 nm uniformly dispersed on the surface. 60,61 Figure 4a shows the X-ray 4aii) respectively. This highly ordered crystalline facet of the Pd nanoparticles synthesized using SARM was also observed in the lattice fringes of the Pd nanoparticles as observed in the high-resolution transmission electron microscopy (HRTEM) image in Figure 3c(iii).…”

Fellows der Electrochemical Society: C. Amatore, K. Amine, P. Atanassov, C. P. Grey, Y. Shao‐Horn und N. Wu / Priestley‐Medaille: G. Richmond / Förderungspreis der Stadt Wien: N. Maulide

“…Im Mittelpunkt seiner Forschung stehen die Elektro‐ und die Bio‐Elektrokatalyse, wobei die Themen vor allem Elektrokatalysatoren für Brennstoffzellen und Elektrolyseure sowie neue Materialien und Technologien für die Energieumwandlung und ‐sammlung sind. In ChemSusChem hat er Elektrokatalysatoren für die Sauerstoffreduktion beschrieben und in ChemElectroChem einen Hybridkatalysator für die Oxidation organischer Säuren . Atanassov gehört dem Editorial Board von ChemElectroChem an.…”