Improving photoexcited carrier separation through Z-scheme W₁₈O₄₉/BiOBr heterostructure coupling carbon quantum dots for efficient photoelectric response and tetracycline photodegradation

Building Z-scheme heterostructure integrating oxygen vacancies seems to effectively encourage photoexcited charge partition and hence photoelectric response and photocatalytic performance. Here, through the inclusion of carbon quantum dots (CQDs) with W₁₈O₄₉/BiOBr (WB) for enhancing electron exchange and band structure control, we have developed one Z-scheme ternary CQD/W₁₈O₄₉/BiOBr heterostructures (CWB) with intense oxygen vacancies. The optimal CWB heterostructure shows superior photocatalytic and photoelectric response execution. The findings indicate that CWB has higher photocatalytic degradation efficiency of tetracycline hydrochloride (TC) at 97 % compared to WB or W₁₈O₄₉ alone. Additionally, the CWB shows a higher photocurrent density, surpassing WB and W₁₈O₄₉ by 2.5 times and 5.4 times. A potential self-supplied photoelectrochemical-type photodetector utilizing CWB displays relatively quick and stable photoelectric response at 0 V. The improved photo-electric performance are linked to the combined impact of separation and redistribution of charges caused by Z-scheme heterostructure and oxygen vacancies, as well as intensive light absorbance by localized surface plasmon resonance. Our research also validates significance of CQDs as cocatalyst in accelerating the splitting of photo carriers in Z-scheme ternary CWB heterostructures, which will stimulate interest in creating advanced photoactive heterojunction substance with carbon nanomaterials.