Water oxidation is an endothermic reaction; BiVO4-based photoanodes with good photothermal and catalytic properties would be propitious to achieve efficient water oxidation in theory. Herein, NiO/amorphous carbon/BiVO4 (NiO/C/BiVO4) and CoOx/amorphous carbon/BiVO4 (CoOx/C/BiVO4) films were prepared by a facile candle flame roasting approach, and further investigated as photoanodes for solar water oxidation. Compared to BiVO4 and C/BiVO4 photoanodes, better water oxidation performance was achieved on the CoOx/C/BiVO4 and NiO/C/BiVO4 photoanodes. At 1.23 V vs. RHE, the water oxidation photocurrent of the CoOx/C/BiVO4 and NiO/C/BiVO4 photoanodes was 2.32 and 2.41 times higher than that of the BiVO4 photoanode, respectively. The water oxidation activity on the CoOx/C/BiVO4 and NiO/C/BiVO4 photoanodes can be well maintained in the range of 84–87% after 120 min of constant reaction, which is higher than that on the BiVO4 photoanode (43% activity retained). The NiO/C/BiVO4 and CoOx/C/BiVO4 photoanodes having higher water oxidation performance can be attributed to the following integrated effects. (1) The p–n heterojunction effect of NiO/BiVO4 and CoOx/BiVO4 drives the directional transfer of holes to CoOx or NiO and weakens the carrier recombination on BiVO4. (2) Amorphous carbon, CoOx and NiO absorb and convert the long wavelength light (λ > 510 nm) into heat to improve the co-catalysis performance of CoOx and NiO, and enable the NiO/C/BiVO4 and CoOx/C/BiVO4 photoanodes for efficient water oxidation. The present work provides two effective BiVO4-based photoanodes for photothermal-enhanced water splitting, which could inspire the design and development of similar materials for photothermal-enhanced solar water splitting.
Bisphenol A (BPA) is an emerging organic pollutant that can disturb endocrine systems at trace levels in water. This study constructed a photocatalyst of cobalt oxide modified bismuth vanadate (CoO x /BiVO 4 ) coupled with peroxymonosulfate (PMS) oxidation system to investigate its photocatalytic mechanism for degrading BPA in wastewater. The CoO x /BiVO 4 photocatalyst was fabricated through a precipitation-hydrothermal method and systematically characterized. The results showed that modifying BiVO 4 with CoO x significantly improved the separation and migration efficiency of photogenerated electron–hole pairs, thereby enhancing the photocatalytic activity of the system. Through active species trapping experiments using different scavengers, singlet oxygen ( 1 O 2 ) and sulfate radicals (SO 4 − ⋅ ) were identified as the predominant reactive oxygen species responsible for BPA degradation. BPA photocatalytic reaction intermediates were analyzed using HPLC-MS, which proposed three possible degradation pathways: (1) Initial hydroxylation of BPA by SO 4 − ⋅ and ⋅ OH radicals; (2) Ring-opening oxidation of hydroxylated intermediates into carboxylic acids; (3) Further mineralization of all intermediates into CO 2 and H 2 O by 1 O 2 and ⋅ OH. In summary, the CoO x /BiVO 4 -PMS system provides an efficient and promising technology for eliminating trace BPA in wastewater via synergistic effects of SO 4 − ⋅ and 1 O 2 . Further optimization of CoO x loading and PMS dosage is still needed to maximize the overall photocatalytic performance.
危险品化学品经营许可证（带存储）