Periodic Reporting for period 1 - 2DTriCat4Energy (2D Trifunctional Catalysts for Electrochemical Energy Conversion and Storage)
Período documentado: 2020-06-01 hasta 2022-05-31
Renewable energy technologies (electrolysers, fuel cells and supercapacitors) are attractive for producing clean energy that can be used to create electricity for buildings and vehicles. Unfortunately, these technologies are still under major research as the 'state-of-the-art' catalysts currently used are uneconomical. This research programme will have economic and social impacts including renewable energy for the population, job creation and may influence the public's negative perception of H2 based fuels for the better. The overall objective for this fellowship is to develop efficient and stable trifunctional catalyst electrodes specifically for water splitting, fuel cells and supercapacitors.
In WP1, various metal oxide-based materials were synthesised through various routes by the researcher which were then screened for the electrochemical applications; OER, ORR and Supercapacitors. Co-precipitation synthesis was used to prepare alpha-Co(OH)2 layered double hydroxide (LDH), beta-Co(OH)2 LDH, NiFe LDH, Ni(OH)2 and NiCo. The researcher also prepared other metal oxides such as RuO2, MnOx, Co3O4, NiO and Fe2O3 by the Adam’s Method which involves the oxidation of a metal salt in molten sodium nitrate. The initial electrochemical investigations of the oxides were carried out for the OER, ORR and supercapacitors.
The Co(OH)2 material, amongst others, was screened as a supercapacitor material. Unfortunately, these materials didn’t show good supercapacitor performance, nor did other, however, from these supercapacitor measurements, the researcher was trained in this area; as already mentioned in section 1.1. From WP2 onwards, the research concentrated predominantly on Co(OH)2 and NiFe LDHs for the OER.
Co(OH) LDHs for the OER
Figure 3 shows the morphology investigations carried out in for the Co(OH)2 LDHs. The SEM and TEM images show that we have successfully obtained 2D/layered Co(OH)2 directly from the co-precipitation. More specifically, we obtained hexagonal-like shapes for our materials. These materials were further optimised (WP3 and WP4) with MXene materials in order to make a composite for the OER that is OER active sites (Co(OH)2) and has increased conductivity (MXenes).
From the LSV curves, it is evident that the hybrid 1 % MXene material exhibits improved OER capabilities when compared to the two pure materials; pure Co and the MXene, as the LSV curve for the 1 % MXene is shifted to more cathodic potentials and reaches higher current densities over the same potential window. Furthermore, the potential at which the 1 % MXene and the pure Co materials reach a current density of 10 mA cm-2 is 1.66 V ± 0.01 vs. Reversible Hydrogen Electrode (RHE) and 1.84 V ± 0.07 vs. RHE, respectively, Figure 2B. The MXene material was very inactive for the OER and doesn’t come close to even reaching a current density of 1 mA cm-2 at the potential of 1.84 V vs. RHE. This is an extremely interesting result as two poor OER materials results in a good OER material when combined. To try and investigate why this is, the researcher used in-situ Raman spectroscopy to gain mechanistic insight into the catalysts. (WP5)
The in-situ Raman measurements were carried out by acquiring Raman spectra at various potentials before and after the thermodynamic potential for OER (i.e. 1.23 V vs. RHE) in an attempt to understand the nature of Co active sites present in the pure Co and 1 % MXene materials during the evolution of O2. In this study, the determination of the active sites for the pure Co is critical for the understanding of the active sites in the 1 % MXene material. For the pure Co material at potential pre-OER (i.e. 0.92 - 1.12 V vs. RHE), the Raman spectra correspond to that of Co3O4.22 During the OER from the potential of 1.32 – 1.72 V, Co3O4 is still the dominant Co oxide however, the intensity of the peak at ~688 cm-1 decreases as the potential increases which could suggest the depletion of Co3O4 in the catalyst layer. Interestingly, at a high OER potential of 1.92 V vs. RHE, the Raman spectrum has changed. At this potential the peak at ~688 cm-1 has disappeared while two Raman peaks at 462 and 576 cm-1 are now present. The peak at 576 cm-1 can be assigned to Co(IV)/CoOx as reported by Bell and co-workers.23 The peak positioned at 462 cm-1 could be associated to the Eg mode in the Co3O4 which indicates that both Co(II/III) and Co(IV) species are present during active O2 evolution for the pure Co material.
(This work is the basis for a manuscript currently submitted and under consideration. The researcher also wrote an invited review on metal oxides and MXene materials for the OER during the fellowship DOI: 10.1016/j.coelec.2022.101021)
The Co(OH)2 material, amongst others, was screened as a supercapacitor material. Unfortunately, these materials didn’t show good supercapacitor performance, nor did other, however, from these supercapacitor measurements, the researcher was trained in this area; as already mentioned in section 1.1. From WP2 onwards, the research concentrated predominantly on Co(OH)2 and NiFe LDHs for the OER.
Co(OH) LDHs for the OER
Figure 3 shows the morphology investigations carried out in for the Co(OH)2 LDHs. The SEM and TEM images show that we have successfully obtained 2D/layered Co(OH)2 directly from the co-precipitation. More specifically, we obtained hexagonal-like shapes for our materials. These materials were further optimised (WP3 and WP4) with MXene materials in order to make a composite for the OER that is OER active sites (Co(OH)2) and has increased conductivity (MXenes).
From the LSV curves, it is evident that the hybrid 1 % MXene material exhibits improved OER capabilities when compared to the two pure materials; pure Co and the MXene, as the LSV curve for the 1 % MXene is shifted to more cathodic potentials and reaches higher current densities over the same potential window. Furthermore, the potential at which the 1 % MXene and the pure Co materials reach a current density of 10 mA cm-2 is 1.66 V ± 0.01 vs. Reversible Hydrogen Electrode (RHE) and 1.84 V ± 0.07 vs. RHE, respectively, Figure 2B. The MXene material was very inactive for the OER and doesn’t come close to even reaching a current density of 1 mA cm-2 at the potential of 1.84 V vs. RHE. This is an extremely interesting result as two poor OER materials results in a good OER material when combined. To try and investigate why this is, the researcher used in-situ Raman spectroscopy to gain mechanistic insight into the catalysts. (WP5)
The in-situ Raman measurements were carried out by acquiring Raman spectra at various potentials before and after the thermodynamic potential for OER (i.e. 1.23 V vs. RHE) in an attempt to understand the nature of Co active sites present in the pure Co and 1 % MXene materials during the evolution of O2. In this study, the determination of the active sites for the pure Co is critical for the understanding of the active sites in the 1 % MXene material. For the pure Co material at potential pre-OER (i.e. 0.92 - 1.12 V vs. RHE), the Raman spectra correspond to that of Co3O4.22 During the OER from the potential of 1.32 – 1.72 V, Co3O4 is still the dominant Co oxide however, the intensity of the peak at ~688 cm-1 decreases as the potential increases which could suggest the depletion of Co3O4 in the catalyst layer. Interestingly, at a high OER potential of 1.92 V vs. RHE, the Raman spectrum has changed. At this potential the peak at ~688 cm-1 has disappeared while two Raman peaks at 462 and 576 cm-1 are now present. The peak at 576 cm-1 can be assigned to Co(IV)/CoOx as reported by Bell and co-workers.23 The peak positioned at 462 cm-1 could be associated to the Eg mode in the Co3O4 which indicates that both Co(II/III) and Co(IV) species are present during active O2 evolution for the pure Co material.
(This work is the basis for a manuscript currently submitted and under consideration. The researcher also wrote an invited review on metal oxides and MXene materials for the OER during the fellowship DOI: 10.1016/j.coelec.2022.101021)
- List the conferences attended and seminar talks
March 2022 Irish Chemistry Young Chemists' Network (ICI YCN) (Invited)
Feb 2022 IUPAC Global Women’s Breakfast, IPS Academy Indore, India (Online) (Invited)
April 2022 Technical University of Berlin for the Clara Immerwahr award ceremony, Figure 7. (Invited)
May 2021 Electrochemical Society (ECS) Chicago (Invited)
Nov 2020 Scanlon Electrochemistry Webinars, 30th November 2020. (Invited) (Youtube channel: https://www.youtube.com/channel/UCZwmF5OUdS9emmGwRBwVXhQ/videos(se abrirá en una nueva ventana))
- List of scientific publications and other dissemination activities
All of the papers below include reference to this MSCA fellowship with the sentence:
‘M.P.B. would like to acknowledge the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 884318 (TriCat4Energy).’
Published
1. The Potential of MXene Materials as a Component in the Catalyst Layer for the Oxygen Evolution Reaction, Michelle P. Browne, Daire Tyndall and Valeria Nicolosi, Current Opinion in Electrochemistry, 2022, in Press. (Emerging Opinions Special Issue – Invited).
2. Post-synthetic treatment of nickel–iron layered double hydroxides for the optimum catalysis of the oxygen evolution reaction, Daire Tyndall, Sonia Jaskaniec, Brian Shortall, Ahin Roy, Lee Gannon, Katie O’Neill, Michelle P. Browne, João Coelho, Cormac McGuinness, Georg S. Duesberg & Valeria Nicolosi, npj 2D Materials and Applications, 2021, 5, 73.
3. Oxygen evolution catalysts under proton exchange membrane conditions in a conventional three electrode cell vs. electrolyser device: a comparison study and a 3D-printed electrolyser for academic labs, Michelle P. Browne, James Dodwell, Filip Novotny, Paul R. Shearing, Valeria Nicolosi, Dan J.L. Brett and Martin Pumera, Journal of Materials Chemistry A, 2021, 9, 9113-9123.
March 2022 Irish Chemistry Young Chemists' Network (ICI YCN) (Invited)
Feb 2022 IUPAC Global Women’s Breakfast, IPS Academy Indore, India (Online) (Invited)
April 2022 Technical University of Berlin for the Clara Immerwahr award ceremony, Figure 7. (Invited)
May 2021 Electrochemical Society (ECS) Chicago (Invited)
Nov 2020 Scanlon Electrochemistry Webinars, 30th November 2020. (Invited) (Youtube channel: https://www.youtube.com/channel/UCZwmF5OUdS9emmGwRBwVXhQ/videos(se abrirá en una nueva ventana))
- List of scientific publications and other dissemination activities
All of the papers below include reference to this MSCA fellowship with the sentence:
‘M.P.B. would like to acknowledge the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 884318 (TriCat4Energy).’
Published
1. The Potential of MXene Materials as a Component in the Catalyst Layer for the Oxygen Evolution Reaction, Michelle P. Browne, Daire Tyndall and Valeria Nicolosi, Current Opinion in Electrochemistry, 2022, in Press. (Emerging Opinions Special Issue – Invited).
2. Post-synthetic treatment of nickel–iron layered double hydroxides for the optimum catalysis of the oxygen evolution reaction, Daire Tyndall, Sonia Jaskaniec, Brian Shortall, Ahin Roy, Lee Gannon, Katie O’Neill, Michelle P. Browne, João Coelho, Cormac McGuinness, Georg S. Duesberg & Valeria Nicolosi, npj 2D Materials and Applications, 2021, 5, 73.
3. Oxygen evolution catalysts under proton exchange membrane conditions in a conventional three electrode cell vs. electrolyser device: a comparison study and a 3D-printed electrolyser for academic labs, Michelle P. Browne, James Dodwell, Filip Novotny, Paul R. Shearing, Valeria Nicolosi, Dan J.L. Brett and Martin Pumera, Journal of Materials Chemistry A, 2021, 9, 9113-9123.