The presence of pharmaceutical compound (i.e., acetaminophen) in aquatic environment has been declared as environmental issue since researchers found that it has potential risk to human health. Photocatalytic process as a promising method for waste degradation commonly employs titanium dioxide, TiO₂. However, TiO₂ has narrow light absorption and rapid charge recombination resulting in ineffective photocatalytic activity. In this study, silica – carbon quantum dots (Si-CQDs) from rice husk are decorated into TiO₂ matrix through facile mixing approach to minimize the limitations of TiO₂. Preliminary studies regarding TiO₂ transformation and Si-CQDs incorporation in various amount were systematically investigated. It is observed that 1 wt% is the optimum amount of Si-CQDs in composite in order to maximize the photocatalytic ability of TiO₂. Under sunlight irradiation, 1 wt% Si-CQDs/TiO₂ composite is able to completely degrade 5 mg/L of acetaminophen within 240 min (33.3 % faster than pure TiO₂). The excellent performance of the composite is attributed to synergistic effect of Si-CQDs addition on TiO₂ surface, which acted as photo sensitizer and electron trapper. Si-CQDs extend light absorption of TiO₂ by reducing band gap energy from 3.20 to 3.12 eV, as confirmed by UV–vis Diffuse Reflectance Spectroscopy (DRS) spectra. Photoluminescence (PL) spectra and N₂ sorption isotherm reveal that Si-CQDs addition prolongs the lifetime of charge separation and improves surface area (17 % larger than TiO₂), respectively. The composite of Si-CQDs/TiO₂ also demonstrates good stability which is beneficial for pharmaceutical waste removal in the future.

自从研究人员发现在水生环境中存在药用化合物（即对乙酰氨基酚）以来，就已经将其宣布为环境问题，因为研究人员发现该化合物对人体健康具有潜在风险。作为一种有希望的废物降解方法，光催化工艺通常使用二氧化钛TiO ₂。然而，TiO ₂具有窄的光吸收和快速的电荷复合，导致无效的光催化活性。在这项研究中，通过简便的混合方法将稻壳中的二氧化硅-碳量子点（Si-CQDs）装饰到TiO ₂基质中，以最小化TiO ₂的限制。TiO _2的初步研究系统地研究了各种形式的转变和Si-CQDs的掺入。观察到为了使TiO ₂的光催化能力最大化，在复合物中Si-CQD的最佳量为1重量％。在阳光照射下，1 wt％Si-CQDs / TiO ₂复合材料能够在240分钟内完全降解5 mg / L对乙酰氨基酚（比纯TiO ₂快33.3％）。复合材料的优异性能归因于Si-CQDs在TiO ₂表面上的协同作用，起到光敏剂和电子陷阱的作用。Si-CQD扩展了TiO _2的光吸收通过将带隙能量从3.20 eV降低到3.12 eV，已通过UV-vis漫反射光谱（DRS）光谱证实。光致发光（PL）光谱和N ₂吸附等温线表明，添加Si-CQDs可以延长电荷分离的寿命并改善表面积（比TiO ₂大17％）。Si-CQDs / TiO ₂的复合材料还显示出良好的稳定性，这有利于将来去除制药废物。