Enhanced photo-induced charge generation of floating sulfur-doped TiO2 double-walled nanotubes for efficient sunlight-driven photocatalytic degradation of bisphenol A
Bibliographic record
Abstract
Floating photocatalysts are an innovative class of immobilized semiconductors that can address the limitations of traditional photocatalysis by directly harvesting light, enhancing oxygen transfer from the air, and enabling easy photocatalyst recovery. In the present study, we developed a novel ultrasound-assisted solvothermal method to synthesize sulfur-doped TiO 2 nanotubes (S-TNT). The floating photocatalysts were prepared by immobilizing S-TNT onto buoyant polyurethane foam (PUF) with an open-cell structure using a wet chemical deposition method. The synthesis yielded double-walled TNT doped with 3 nm sulfur nanodots. The ultrasound-assisted solvothermal synthesis method using thiourea as a sulfur precursor resulted in the incorporation of anionic sulfur (S 2− ) and cationic sulfur (S 4+ , S 6+ ) into TNT. Among different sulfur dopants (0.5–2 wt%), 1 wt% (S-TNT-1) was optimal to achieve superior optical properties, enhanced photo-induced charge generation, and effective electron-hole pair separation. Compared to bare TNT, the specific surface area of S-TNT-1 increased from 110 to 267 m 2 /g, while the bandgap energy decreased from 3 to 2.48 eV. The photocurrent density of S-TNT-1 (0.6 mA/cm 2 ) was threefold higher than that of TNT. Evaluating operating parameters indicated that >96 % of 10 mg/L Bisphenol A (BPA) was degraded with 0.2 g S-TNT-1@PUF at pH = 8 after 75 min of simulated sunlight irradiation. This degradation followed first-order kinetics, with an apparent rate constant of 0.05 min −1 , in which • OH was the reactive species that contributed most (31 %).
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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) | 0.000 | 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 teacher head, 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".