制备ZnO/CdS/Au异质结用于可见光催化降解低浓度甲醛

采用水热法和化学浴沉积法制备了ZnO/CdS/Au异质结光催化剂，用于可见光下室温去除低浓度甲醛。通过XRD、SEM、TEM、XPS、UV、PL、PEC、EIS等手段对ZnO/CdS/Au异质结光催化剂的光学性能、光电性能进行表征。结果表明，Au负载的ZnO/CdS纳米棒组成的微米花状结构中，异质结和金属等离子体效应能拓宽光谱吸收范围，抑制半导体缺陷发光，促进光吸收以及光生电子空穴的分离和迁移；所制备的ZnO/CdS/Au异质结光催化剂对甲醛的去除具有优异性能，室温下2 h即可将反应舱内低质量浓度甲醛(1.25 mg·m⁻³)降至0.025 mg·m⁻³以下，且经过8次重复使用后催化剂活性没有明显下降。此外，影响甲醛去除的因素，如催化剂种类、光照波长、甲醛初始质量浓度、相对湿度也进行了研究和探讨。该研究结果对低浓度甲醛的室温去除具有理论指导意义。

Synthesis of ZnO/CdS/Au heterojunction for photocatalytic degradation of formaldehyde at room temperature under visible light

ZnO/CdS/Au heterojunction photocatalysts were synthesized via hydrothermal and chemical bath deposition methods for the removal of low-concentration formaldehyde under visible light at room temperature. The optical and photoelectronic characteristics of the ZnO/CdS/Au heterojunction photocatalyst were systematically investigated utilizing a suite of analytical techniques, including XRD, SEM, TEM, XPS, UV, PL, PEC, EIS, and other complementary methods. The results revealed that the Au-decorated ZnO/CdS exhibited a micrometer-scale flower-like morphology composed of nanorods. The formation of the heterojunction and the plasmonic effect induced by the metal component led to an expansion of the spectral absorption range, suppression of the defect-related luminescence in the semiconductor, and enhancement of light absorption as well as efficient separation and migration of photogenerated electron-hole pairs. The fabricated ZnO/CdS/Au heterojunction photocatalyst demonstrated exceptional performance in the removal of formaldehyde, achieving the reduction of low-mass concentration formaldehyde (1.25 mg·m−3) in a reaction chamber to below 0.025 mg·m−3 within 2 h at room temperature. Moreover, the catalyst retained its activity with negligible degradation after 8 consecutive cycles. Furthermore, this study elucidated the influence of various factors on the removal of formaldehyde, such as the type of catalyst, light wavelength, initial mass concentration of formaldehyde, and relative humidity. A comprehensive discussion of these factors is presented herein. The findings of this research hold significant theoretical implications for the effective abatement of low-concentration formaldehyde at room temperature.