Niobium: a promising Pd co-electrocatalyst for ethanol electrooxidation reactions

Abstract

This work reports the sol-gel synthesis and characterization of Pd x Nb y /C binary electrocatalysts applied to ethanol electrooxidation reactions (EORs). Catalysts were prepared using different Pd/Nb mass ratios (1:0; 1:1; 1:3; 3:1; 0:1) and were supported on Vulcan XC-72 carbon (20 wt%). The materials were characterized by transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, inductively coupled plasma mass spectrometry, and X-ray photoelectron spectroscopy. The EOR catalytic activity was studied by cyclic voltammetry (CV) and chronoamperometry (CA). The results showed that the EOR current density peak using Pd 1 Nb 1 /C (45.5 mA mg −1) was 2.86 times higher than that of commercial Pd/C (15.9 mA mg −1). This catalyst also showed a less positive EOR onset potential and 2.35 times higher current density than Pd/C did in CA. The Pd 1 Nb 1 /C (− 0.54 V) showed onset potential more negative than Pd/C (− 0.50 V) for CO-stripping analysis. Additionally, the addition of Nb in the Pd/C reduces CO ads poisoning of the electrocatalyst. The results suggest that Nb decreases the poisoning effect of CO on the Pd surface due to the bifunctional mechanism in which Nb supplies oxygenated species for CO oxidation at poisoned Pd active sites. No evidence of Pd/Nb alloy formation has been found. The maximization of the bifunctional effect occurs in Pd 1 Nb 1 /C.

Construction of a Voltammetric Sensor Based on Niobium Supported on Zirconium Oxide‐Carbon Nanotubes for the Determination of Favipiravir, an Antiviral Drug Used Against Covid‐19

“…Souza et al. reported that materials containing Nb have also received special attention due to their use in heterogeneous catalysis [32] . Studies have shown that the use of Nb increases the catalytic activity, selectivity and chemical stability of conventional catalysts [32] .…”

“…Souza et al reported that materials containing Nb have also received special attention due to their use in heterogeneous catalysis. [32] Studies have shown that the use of Nb increases the catalytic activity, selectivity and chemical stability of conventional catalysts. [32] Souza et al have also reported that Nb is a possible cocatalyst due to the forbidden energy in the 3.1 to 4 eV band, which is ideal for the catalysis of organic compounds.…”

“…[32] Studies have shown that the use of Nb increases the catalytic activity, selectivity and chemical stability of conventional catalysts. [32] Souza et al have also reported that Nb is a possible cocatalyst due to the forbidden energy in the 3.1 to 4 eV band, which is ideal for the catalysis of organic compounds. [33] Nb electrocatalysts also have high electrochemically active surface area.…”

Electrochemical Nucleation and Growth of Pd-Co Alloy Nanoparticles from the Reline Deep Eutectic Solvent

“…The synthesis methods of nanomaterials are numerous, however, most of them involve a complicated series of steps: they are expensive and unfriendly to the environment, namely: chemical methods, [1][2][3][4] incipient wetness impregnation, 5 sol-gel, 6 co-precipitation, 7 hydrothermal, 8,9 electrospinning-carbonization process, 10 physical vapor deposition (PVD), 11 galvanic replacement 12 etc. Notwithstanding, electrodeposition leads the user to finer control of the experimental set ups because it displays the opposite of what we mentioned initially and allows the formation of nanoparticles, NPs, in one single step without any additives and chemical reactants, especially when the so-called deep eutectic solvents, DES, 13 are used as the electrolytic bath.…”