Electrocatalysis of Methanol Oxidation in Alkaline Electrolytes over Novel Amorphous Fe/Ni Biphosphate Material Prepared by Different Techniques

Mai M Khalaf; Hany M Abd El-Lateef; Van-Duong Dao; Ibrahim M A Mohamed

doi:10.3390/nano12193429

Electrocatalysis of Methanol Oxidation in Alkaline Electrolytes over Novel Amorphous Fe/Ni Biphosphate Material Prepared by Different Techniques

Nanomaterials (Basel). 2022 Sep 30;12(19):3429. doi: 10.3390/nano12193429.

Authors

Mai M Khalaf^{1

2}, Hany M Abd El-Lateef^{1

2}, Van-Duong Dao³, Ibrahim M A Mohamed²

Affiliations

¹ Department of Chemistry, College of Science, King Faisal University, Al-Ahsa 31982, Saudi Arabia.
² Department of Chemistry, Faculty of Science, Sohag University, Sohag 82524, Egypt.
³ Faculty of Biotechnology, Chemistry and Environmental Engineering, Phenikaa University, Hanoi 10000, Vietnam.

Abstract

In this work, novel phosphate materials based on bimetallic character (Fe and Ni) were introduced by different chemical fabrication methods, the reflux method (FeNiP-R) and the sol-gel technique (FeNiP-S), and evaluated as non-precious electrodes for methanol electrooxidation in KOH electrolytes. The designed FeNiP-R and FeNiP-S samples were investigated using different characterization techniques, namely TEM, SEM, XPS, BET, DLS, and FT-IR, to describe the impact of the fabrication technique on the chemistry, morphology, and surface area. The characterization techniques indicate the successful fabrication of nanoscale-sized particles with higher agglomeration by the sol-gel technique compared with the reflux strategy. After that, the electrochemical efficiency of the fabricated FeNiP-R and FeNiP-S as electrodes for electrocatalytic methanol oxidation was studied through cyclic voltammetry (CV) at different methanol concentrations and scan rates in addition to impedance analysis and chronoamperometric techniques. From electrochemical analyses, a sharp improvement in the obtained current values was observed in both electrodes, FeNiP-R and FeNiP-S. During the MeOH electrooxidation over FeNiP-S, the current value was improved from 0.14 mA/cm² at 0.402 V to 2.67 mA/cm² at 0.619 V, which is around 109 times the current density value (0.0243 mA/cm² at 0.62 V) found in the absence of MeOH. The designed FeNiP-R electrode showed an improved electrocatalytic character compared with FeNiP-S at different methanol concentrations up to 80 mmol/L. The enhancement of the anodic current density and charge transfer resistance indicates the methanol electrooxidation over the designed bimetallic Fe/Ni-phosphates.

Keywords: Fe/Ni; biphosphates; electrocatalysis; methanol electrooxidation; sol–gel.

Grants and funding

This work was supported through the annual funding track by the Deanship of Scientific Research, Vice Presidency for Graduate Studies and Scientific Research, King Faisal University, Saudi Arabia (GRANT1667).