School of Chemical and Environmental Engineering, China University of Mining and Technology (Beijing), Beijing 100083, PR China.
School of Chemical and Environmental Engineering, China University of Mining and Technology (Beijing), Beijing 100083, PR China.
J Environ Manage. 2024 Nov;370:122434. doi: 10.1016/j.jenvman.2024.122434. Epub 2024 Sep 11.
Photothermal catalytic oxidation is a promising and sustainable method for the degradation of indoor formaldehyde (HCHO). However, the excessively high surface temperature of existing photothermal catalysts during catalysis hinders the effective adsorption and degradation of formaldehyde under static conditions. Catalyst loading and oxygen vacancies (OVs) modulation are commonly employed strategies to reduce the photothermal catalytic temperature and enhance the efficiency of photothermal catalytic oxidation. In this work, a p-n type CuO/TiO heterojunction is successfully loaded onto diatomite using a wet precipitation method. Under the irradiation of a 300W xenon lamp, the prepared composite material achieved a 100% removal rate of HCHO within 2 h, with a 98% conversion rate to CO, surpassing the performance of both individual photocatalysts and thermocatalysts. Additionally, by adjusting conditions such as light irradiation and temperature, we have demonstrated that this material exhibits synergistic photothermal catalytic properties. Based on HRTEM, XPS, Raman, and EPR analyses, the introduction of diatomite as a catalyst support was shown to effectively increase the number of OVs. Experimental results, along with O-TPD, photoelectrochemical characterization, and radical detection, demonstrate that the presence of OVs enhances the oxidative efficiency of both photocatalysis and thermocatalysis, as well as the UV-Vis-IR photothermal catalytic performance. The ternary composite material generates weak hydroxyl (OH) and superoxide (O) radical under high-temperature with dark conditions, indicating its catalytic oxidation activity under this condition. The increase in temperature and the expansion of the spectral range both enhance the generation of these radicals. In summary, this work demonstrates that the use of diatomite as a support increases the material's specific surface area and OVs content, thereby enhancing adsorption and photothermal catalysis. It elucidates the enhanced catalytic degradation mechanism of this mineral-based photothermal catalyst.
光热催化氧化是一种很有前途和可持续的方法，可用于降解室内甲醛（HCHO）。然而，现有的光热催化剂在催化过程中表面温度过高，阻碍了其在静态条件下对甲醛的有效吸附和降解。催化剂负载和氧空位（OVs）调制是降低光热催化温度和提高光热催化氧化效率的常用策略。在这项工作中，通过湿沉淀法成功地将 p-n 型 CuO/TiO 异质结负载到硅藻土上。在 300W 氙灯的照射下，所制备的复合材料在 2 小时内实现了 HCHO 的 100%去除率，CO 的转化率达到 98%，超过了单一光催化剂和热催化剂的性能。此外，通过调节光照和温度等条件，我们证明了该材料具有协同光热催化性能。基于 HRTEM、XPS、Raman 和 EPR 分析，引入硅藻土作为催化剂载体被证明可以有效地增加 OVs 的数量。实验结果以及 O-TPD、光电化学表征和自由基检测表明，OVs 的存在增强了光催化和热催化的氧化效率，以及 UV-Vis-IR 光热催化性能。在高温黑暗条件下，三元复合体制备的材料会产生较弱的羟基（OH）和超氧（O）自由基，表明其在这种条件下具有催化氧化活性。温度升高和光谱范围扩大都会增强这些自由基的生成。综上所述，本工作表明，使用硅藻土作为载体可以增加材料的比表面积和 OVs 含量，从而增强吸附和光热催化。它阐明了这种基于矿物质的光热催化剂增强催化降解的机制。
