Boosting CO2-to-CO Evolution Using a Bimetallic Diketopyrrolopyrrole Tethered Rhenium Bipyridine Catalyst
Bibliographic record
Abstract
The use of homogenous electro- and photo- catalysis involving molecular catalysts offers valuable insight into reaction mechanisms as it relates to the structure-function of these tunable systems. However, supported molecular catalysts (i.e., hybrid electrodes) are multiplexed and not fully understood with regards to specific support-catalyst interactions. Even so, it still remains that catalyst activity for CO2 electroreduction can be tuned by modifying specific functional groups to achieve performance enhancement. Herein, a series of derivatized [Re(bpy)(CO)3Cl] catalysts were prepared with molecular structures having variability in both the number of Re-centers and π-conjugated diketopyrrolopyrrole (DPP) units. While tethering [Re(bpy)(CO)3Cl] to the DPP unit had a negligible effect on molecular electro- and photo- catalyst properties in organic solvent, the DPP chromophore enabled facile coupling of two [Re(bpy)(CO)3Cl] moieties. As a homogenous species, the bimetallic system effectively doubles the rate of CO2-to-CO conversion in the reaction-diffusion layer achieving a TOFCO = 1000 s-1 and FEco% = 98 % for up to 6 hours of electrolysis as the two catalytic centers act independently. Immobilization onto carbon hybrid electrodes was found to evolve H2, where the ratio of CO:H2 produced during electrolysis depended on both the molecular structure of the catalyst and the additive(s) to the carbon surface used to suppress the hydrogen evolution reaction (HER). Introducing a commercial DPP-based polymer and/or colloid imprinted carbons (CICs) into carbon paper favours CO evolution from the catalyst by suppressing the HER at carbon and by dispersing the molecular catalyst across a larger more wettable surface to mitigate mass transport limitations. Once again, the bimetallic catalyst has the highest activity in comparison to the monometallic analogues, with a selectivity (FEco% = 53%), activity (TOF = 39 hr-1), and longevity (active for up to 5 hours) for CO2-to-CO evolution from aqueous electrolyte.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".