Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Ocean Science and Technology, Dalian University of Technology, Panjin 124221, China.
College of Sciences, Shihezi University, Shihezi 832003, China.
Sci Total Environ. 2022 Jul 15;830:154818. doi: 10.1016/j.scitotenv.2022.154818. Epub 2022 Mar 25.
Under the background of indoor air formaldehyde decontamination, a freestanding ultra-light assembly was fabricated via ice-templating approach starting from MnO nanoparticles and environmentally benign agar powder. The 3D composite of agar and MnO (AM-3D) was comparatively studied with powdered counterparts (including pure MnO and mixture of agar and MnO) and the 3D-structured agar for formaldehyde oxidation, and their physicochemical properties were examined with XRD, ATR, SEM, XPS, isothermal N adsorption, ESR, Raman, CO-TPR and O-TPD. For the single test of formaldehyde oxidation, the AM-3D catalyst exhibited 62.0%-67.0% removal percentage for ~400 mg/m formaldehyde, which did not demonstrate significant advantage over the control samples. However, thanks to the porous 3D agar scaffold with large spatial volume that could promote a rapid gas-phase formaldehyde concentration reduction, and the strong interaction between the dispersed MnO particles and agar substrate that could afford a large amount of reactive oxygen species to further oxidize the adsorbed formaldehyde, the AM-3D composite was a much better HCHO-to-CO converter and possessed much more advantageous stability for repeated cycles of formaldehyde oxidation: even after ten cycles, there was still 41.7% of formaldehyde removed. Furthermore, the viable sunlight irradiation could easily restore the activity of the used AM-3D catalyst back to the level approaching that of the fresh one. Finally, reaction pathways were put forward via the infrared spectroscopic and ion chromatographic investigations on the surface intermediates of the spent materials.
在室内空气甲醛净化的背景下，本研究通过冰模板法，以 MnO 纳米粒子和环境友好的琼脂粉为起始原料，制备了一种独立式超轻组件。将琼脂和 MnO 的 3D 复合材料（AM-3D）与粉末状的对应物（包括纯 MnO 和琼脂与 MnO 的混合物）和用于甲醛氧化的 3D 结构琼脂进行了比较研究，并通过 XRD、ATR、SEM、XPS、等温 N 吸附、ESR、拉曼、CO-TPR 和 O-TPD 对其物理化学性质进行了研究。在单一的甲醛氧化测试中，AM-3D 催化剂对约 400mg/m 的甲醛的去除率为 62.0%-67.0%，这与对照样品相比并没有明显的优势。然而，由于具有大空间体积的多孔 3D 琼脂支架可以促进气相甲醛浓度的快速降低，并且分散的 MnO 颗粒与琼脂基质之间的强相互作用可以提供大量的活性氧物种来进一步氧化吸附的甲醛，因此 AM-3D 复合材料是一种更好的 HCHO 到 CO 的转化剂，并且在重复的甲醛氧化循环中具有更好的稳定性：即使经过十次循环，仍有 41.7%的甲醛被去除。此外，可用的阳光照射可以很容易地将使用过的 AM-3D 催化剂的活性恢复到接近新鲜催化剂的水平。最后，通过对用过的材料表面中间体的红外光谱和离子色谱研究，提出了反应途径。
