Fabrication of bimetallic Ni‐Ag/CNFs nanoparticles as a catalyst in direct alcohol fuel cells (DAFCs)

Abstract

In the present work, an attempt to improve DAFC by replacing platinum with cheaper materials. Ni acetate-Ag nitrate supported by carbon nanofibers with three different samples (S1 95-5, S2 90-10, and S3 80-20%) for Ni and Ag, respectively, were synthesized by using the electrospinning method and then calcined under an Argon atmosphere at 900 C. Numerous analysis methods were employed to examine the chemical structure, the morphology, and the electrochemical (EC) features. The scanning electron microscope (SEM) confirms that all samples with different Ag concentrations exhibit good nanofiber morphology and a clear appearance of the nanoparticles. According to energy dispersive X-ray (EDX) mapping, the results prove that the carbonized polyvinyl alcohol nanofibers (PVANFs) have a consistent and even distribution of nickel and silver with an accurate percentage as previously prepared by molar ratio. Transmission electron microscope (TEM) shows that the interior structure has an amorphous carbon nanofiber structure with embedded crystalline spheres of silver and nickel. From X-ray diffraction (XRD) analysis, no hydroxide or oxide phases can be identified in the XRD pattern, which prove the existence of Ni-Ag nanoparticles in the metallic phase. For the electrooxidation of ethanol and methanol, the samples' electrocatalytic characteristics were examined. The effects of the electrolyte concentration, scan rate on the catalytic performance and electrode stability were studied using cyclic voltammetry (CV), chronoamperometry, and electrochemical impedance measurements (EIS). CV, chronoamperometry, and EIS reveal that the S2 sample has the best, superior electro-oxidation activity for both methanol and ethanol with the highest current density. Hence, This research provided a promising approach to fabricating a promising bimetallic Ni-Ag/CNFs catalyst to replace platinum in direct DAFCs.

NiCoMo nanoparticles as an efficient electrocatalyst for methanol electro‐oxidation in alkaline media

“…As seen in Figure7, this movement can be understood as an increase in the concentration of organic residues that do not oxidize, indicating the requirement for a higher potential. Furthermore, observed is the fact that the maximum current value and higher catalytic activity are at 2 M. For Ni/CNf sample with changing the methanol concentration, the current density increased from 20 to 26 at 0.6 V while for Co/CNF sample the current density increased from 13 to 20 with increasing methanol concentration from 0 to 2 M at 0.6 V. For the sample Ni Co Mo/CNF, The current density shows a higher increase as the methanol concentration raised where the current density increased from 45 to 99.8 at 0.6 V. The optimum concentration is found to be 2 M for all samples in agreement with the literature3,36 and unfortunately increasing concentration of methanol could increase the toxicity and crossover of methanol 35,37. The relationship between concentration and maximum current density is explained in the inset of Figure7A-C.Ni Co Mo/CNFs receive a higher current density of 99.8 mA.…”

“…Considering resource scarcity, environmental concerns, and price fluctuations, fossil fuels cannot be regarded as the conventional energy source in the foreseeable future. Consequently, one of the most important challenges of the twenty‐first century is the development of renewable energy alternatives that can reduce reliance on fossil fuels 1–3 . Direct alcohol fuel cells (DAFCs), which can directly turn the chemical energy that alcohols store into electrical power, have drawn more interest lately because of their numerous benefits, such as quick mechanical refueling, low emissions, high energy density, high efficiency, and ease of use 3–6 …”

“…Despite not being a precious metal, nickel is a more effective electrocatalyst for the oxidation of methanol than noble metals, achieving higher catalytic activity and current densities. The most promising MOR catalysts under alkaline conditions among the earth‐abundant elements are the bimetallic alloys based on Ni, such as NiAg, 3 NiCu, 11 NiPd, 2 NiMn, 10 NiCo, 12 and NiSn 13 . Consequently, several transition metal nanoparticles (NPs) were presented as options for non‐precious electrocatalysts to supplant the Pt‐based materials.…”

Valuation of bimetallic Pd/Ni nanoparticles catalyst for the applications in direct methanol fuel cells

“…Direct alcohol fuel cells (DAFCs) as portable applications have received a lot of attention recently due to several superior advantages over equivalent devices fuelled with hydrogen. 1,2 Direct methanol fuel cells (DMFCs) are the most popular type of DAFC. Due to Pt and Ptbased alloys' excellent catalytic activity in numerous processes, including the electrooxidation of tiny organic molecules, the majority of DMFC research to date has been conducted in acidic media.…”

“…Direct alcohol fuel cells (DAFCs) as portable applications have received a lot of attention recently due to several superior advantages over equivalent devices fuelled with hydrogen 1,2 . Direct methanol fuel cells (DMFCs) are the most popular type of DAFC.…”