Unexpected Negative Performance of PdRhNi Electrocatalysts toward Ethanol Oxidation Reaction
Direct ethanol fuel cells (DEFCs) need newly designed novel affordable catalysts for commercialization. Additionally, unlike bimetallic systems, trimetallic catalytic systems are not extensively investigated in terms of their catalytic potential toward redox reactions in fuel cells. Furthermore, the...
| Main Authors: | , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2023-04-01
|
| Series: | Micromachines |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2072-666X/14/5/957 |
| _version_ | 1797599059973767168 |
|---|---|
| author | Ahmed ElSheikh James McGregor |
| author_facet | Ahmed ElSheikh James McGregor |
| author_sort | Ahmed ElSheikh |
| collection | DOAJ |
| description | Direct ethanol fuel cells (DEFCs) need newly designed novel affordable catalysts for commercialization. Additionally, unlike bimetallic systems, trimetallic catalytic systems are not extensively investigated in terms of their catalytic potential toward redox reactions in fuel cells. Furthermore, the Rh potential to break the ethanol rigid C-C bond at low applied potentials, and therefore enhance the DEFC efficiency and CO<sub>2</sub> yield, is controversial amongst researchers. In this work, two PdRhNi/C, Pd/C, Rh/C and Ni/C electrocatalysts are synthesized via a one-step impregnation process at ambient pressure and temperature. The catalysts are then applied for ethanol electrooxidation reaction (EOR). Electrochemical evaluation is performed using cyclic voltammetry (CV) and chronoamperometry (CA). Physiochemical characterization is pursued using X-ray diffraction (XRD), transmission electron microscope (TEM), energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS). Unlike Pd/C, the prepared Rh/C and Ni/C do not show any activity for (EOR). The followed protocol produces alloyed dispersed PdRhNi nanoparticles of 3 nm in size. However, the PdRhNi/C samples underperform the monometallic Pd/C, even though the Ni or Rh individual addition to it enhances its activity, as reported in the literature herein. The exact reasons for the low PdRhNi performance are not fully understood. However, a reasonable reference can be given about the lower Pd surface coverage on both PdRhNi samples according to the XPS and EDX results. Furthermore, adding both Rh and Ni to Pd exercises compressive strain on the Pd lattice, noted by the PdRhNi XRD peak shift to higher angles. |
| first_indexed | 2024-03-11T03:29:15Z |
| format | Article |
| id | doaj.art-6c8fdc6c7ede48be9dc7b63a87571e8f |
| institution | Directory Open Access Journal |
| issn | 2072-666X |
| language | English |
| last_indexed | 2024-03-11T03:29:15Z |
| publishDate | 2023-04-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Micromachines |
| spelling | doaj.art-6c8fdc6c7ede48be9dc7b63a87571e8f2023-11-18T02:29:41ZengMDPI AGMicromachines2072-666X2023-04-0114595710.3390/mi14050957Unexpected Negative Performance of PdRhNi Electrocatalysts toward Ethanol Oxidation ReactionAhmed ElSheikh0James McGregor1Department of Chemical & Biological Engineering, University of Sheffield, Sheffield S1 3JD, UKDepartment of Chemical & Biological Engineering, University of Sheffield, Sheffield S1 3JD, UKDirect ethanol fuel cells (DEFCs) need newly designed novel affordable catalysts for commercialization. Additionally, unlike bimetallic systems, trimetallic catalytic systems are not extensively investigated in terms of their catalytic potential toward redox reactions in fuel cells. Furthermore, the Rh potential to break the ethanol rigid C-C bond at low applied potentials, and therefore enhance the DEFC efficiency and CO<sub>2</sub> yield, is controversial amongst researchers. In this work, two PdRhNi/C, Pd/C, Rh/C and Ni/C electrocatalysts are synthesized via a one-step impregnation process at ambient pressure and temperature. The catalysts are then applied for ethanol electrooxidation reaction (EOR). Electrochemical evaluation is performed using cyclic voltammetry (CV) and chronoamperometry (CA). Physiochemical characterization is pursued using X-ray diffraction (XRD), transmission electron microscope (TEM), energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS). Unlike Pd/C, the prepared Rh/C and Ni/C do not show any activity for (EOR). The followed protocol produces alloyed dispersed PdRhNi nanoparticles of 3 nm in size. However, the PdRhNi/C samples underperform the monometallic Pd/C, even though the Ni or Rh individual addition to it enhances its activity, as reported in the literature herein. The exact reasons for the low PdRhNi performance are not fully understood. However, a reasonable reference can be given about the lower Pd surface coverage on both PdRhNi samples according to the XPS and EDX results. Furthermore, adding both Rh and Ni to Pd exercises compressive strain on the Pd lattice, noted by the PdRhNi XRD peak shift to higher angles.https://www.mdpi.com/2072-666X/14/5/957ethanol oxidation reactiontrimetallic nanoparticlesRh effectsurface metal segregation |
| spellingShingle | Ahmed ElSheikh James McGregor Unexpected Negative Performance of PdRhNi Electrocatalysts toward Ethanol Oxidation Reaction Micromachines ethanol oxidation reaction trimetallic nanoparticles Rh effect surface metal segregation |
| title | Unexpected Negative Performance of PdRhNi Electrocatalysts toward Ethanol Oxidation Reaction |
| title_full | Unexpected Negative Performance of PdRhNi Electrocatalysts toward Ethanol Oxidation Reaction |
| title_fullStr | Unexpected Negative Performance of PdRhNi Electrocatalysts toward Ethanol Oxidation Reaction |
| title_full_unstemmed | Unexpected Negative Performance of PdRhNi Electrocatalysts toward Ethanol Oxidation Reaction |
| title_short | Unexpected Negative Performance of PdRhNi Electrocatalysts toward Ethanol Oxidation Reaction |
| title_sort | unexpected negative performance of pdrhni electrocatalysts toward ethanol oxidation reaction |
| topic | ethanol oxidation reaction trimetallic nanoparticles Rh effect surface metal segregation |
| url | https://www.mdpi.com/2072-666X/14/5/957 |
| work_keys_str_mv | AT ahmedelsheikh unexpectednegativeperformanceofpdrhnielectrocatalyststowardethanoloxidationreaction AT jamesmcgregor unexpectednegativeperformanceofpdrhnielectrocatalyststowardethanoloxidationreaction |