| Cyclic voltammetry, Ni₄, DMF, TBA-BF₄ | A small broad redox feature at −0.8 V vs Fc⁺/⁰ and a sharp wave at −1.7 V vs Fc⁺/⁰ were observed |
|---|---|
| UV–visible spectroscopy, Ni₄/CNT after OER | A distinct blue shift from 407 nm to 393 nm was observed |
| UV–visible spectroscopy, Ni₄/CNT after HER | A weak and poorly resolved band at roughly the same wavelength was detected |
| FESEM | Ni₄/CNT showed irregular, nanoscale spots and aggregates of the Ni₄-complex-rich phase; after HER and OER electrolysis, the spots evolved into larger features with similar morphology |
| HRTEM, post-OER | Lattice fringes with an interplanar spacing of ~0.28 nm were assigned to layered Ni(OH)₂/NiOOH-type phases |
| HRTEM, post-HER | Lattice fringes with an interplanar spacing of ~0.28 nm were assigned to possible NiO/Ni(OH)₂-type domains, consistent with NiO (111) and Ni(OH)₂ (101) planes |
| XPS, Ni 2p₃/₂, post-OER | The peak shifted from 853.8 to 855.6 eV, indicating surface oxidation and the likely formation of Ni(OH)₂/NiOOH-like species |
| XPS, Ni 2p₃/₂, post-HER | A peak persisted near 855.8 eV, suggesting retained NiO/Ni(OH)₂-type domains rather than complete reduction to metallic Ni |
Pankaj Kumar, Joydeb Goura, Munmun Ghosh. “Molecular immobilization of tetranuclear nickel complex for electrocatalytic overall water splitting reaction.” ChemRxiv (). https://doi.org/10.26434/chemrxiv.15007892/v1
Values presented only in plots or images were not transcribed. The main paper refers to supporting information, but no separate supporting information file was available on the ChemRxiv article page