The interaction between Pt and CeO2 under reducing and oxidizing conditions as well as its effect on the thermal stability of Pt/CeO2 were extensively investigated by means of N2 adsorption/desorption, Raman spectroscopy, CO chemisorption, H2 TPR, XRD, and XPS techniques. In situ and ex situ Raman spectroscopy showed that Pt is anchored with the surface oxygen of CeO2 by forming Pt–O–Ce bond during the oxidative treatment of Pt/CeO2. Under the reducing condition, the static CO chemisorption presented that the amount of CO adsorbed on CeO2 is almost equal to that on Pt/CeO2, implying that Pt atom is located on the oxygen vacancy generated on reduced CeO2 surface. Strong Pt–O–Ce bond maintained the textural properties of Pt/CeO2 from oxidative treatment at temperature as high as 800 °C, as evidenced by the XRD patterns and BJH curves of the samples. Selective removal of the surface oxygen of Pt/CeO2 resulted in the decreased thermal stability of Pt/CeO2 due to the loss of Pt–O–Ce bond. Stronger interaction between Pt and CeO2 is observed when the oxidation temperature was increased from 500 to 800 °C, as evidenced by the shift of the surface reduction peak of Pt/CeO2 in H2 TPR to the higher temperature. It is consistent with in situ Raman spectra of Pt/CeO2, which showed that Pt–O–Ce bond became more resistant to the reduction by H2 after the oxidative treatment at 800 °C. Hence, it is concluded that Pt–O–Ce bond plays an important role in improving the thermal stability of Pt/CeO2 upon the oxidative treatment at high temperature. Based on characterization results, the model is proposed to explain the interaction between Pt and CeO2 under the oxidative treatment.

Used nuclear fuel reprocessing represents a unique challenge when dealing with radionuclides such as isotopes of Kr andI due to their volatility and long half-life. Efficient capture of I ( t = 15.7 × 10 years) from the nuclear waste stream can help reduce the risk of releasing I radionuclide into the environment and/or potential incorporation into the human thyroid. Metal organic frameworks have the reported potential to be I adsorbents but the effect of water vapor, generally present in the reprocessing off-gas stream, is rarely taken into account. Moisture-stable porous metal organic frameworks that can selectively adsorb I in the presence of water vapor are thus of great interest. Herein, we report on the I adsorption capacity of two microporous metal organic frameworks at both dry and humid conditions. Single-crystal X-ray diffraction and Raman spectroscopy reveal distinct sorption sites of molecular I within the pores in proximity to the phenyl- and phenol-based linkers stabilized by the I···π and I···O interactions, which allow selective uptake of iodine.

The CO oxidation ability can be modulated by controlling the metal− support interaction of Pt/CeO 2 catalysts. The Pt/(800C)CeO 2 sample prepared by the thermal treatment of ceria at 800 °C before loading Pt maintained the much higher Pt dispersion than Pt/γ-Al 2 O 3 after the thermal aging at 800 °C, indicating its excellent thermal resistance against Pt sintering. In addition, the CO oxidation rate of the Pt/ (800C)CeO 2 catalyst was order of magnitude higher than that of the Pt/CeO 2 catalyst. Such enhanced activity is explained by the weakened Pt−ceria interaction in Pt/ (800C)CeO 2 , which is evidenced by the formation of PtO 2 species that interact weakly with ceria rather than that of Pt−O−Ce species interacting strongly with ceria. The presence of PtO 2 species appears to be essential for the high CO oxidation ability.

Different structural phases (e.g., TT, T, and H) of niobium oxide were synthesized, characterized by XRD and Raman, and utilized for the furfuryl alcohol dehydration and condensation under mild conditions (100 o C and ambient pressure). Furfuryl alcohol conversion was dependent on reaction time and niobium oxide phase. Niobic acid and T/H phase transitional niobium oxide showed higher catalytic activity in comparison to a single crystalline phase niobium oxide. While T/H phase transitional niobium oxide showed higher conversion than that of niobic acid and TT phase niobium oxide, higher C 9-C 15 products' selectivity (> 60%) was obtained with the latter catalysts.

Capture of highly volatile radioactive iodine is a promising application of metal-organic frameworks (MOFs), thanks to their high porosity with flexible chemical architecture. Specifically, strong charge-transfer binding of iodine to the framework enables efficient and selective iodine uptake as well as its long-term storage. As such, precise knowledge of the electronic structure of iodine is essential for a detailed modeling of the iodine sorption process, which will allow for rational design of iodophilic MOFs in the future. Here we probe the electronic structure of iodine in MOFs at variable iodine···framework interaction by Raman and optical absorption spectroscopy at high pressure ( P). The electronic structure of iodine in the straight channels of SBMOF-1 (Ca- sdb, sdb = 4,4'-sulfonyldibenzoate) is modified irreversibly at P > 3.4 GPa by charge transfer, marking a polymerization of iodine molecules into a 1D polyiodide chain. In contrast, iodine in the sinusoidal channels of SBMOF-3 (Cd- sdb) retains its molecular (I) character up to at least 8.4 GPa. Such divergent high-pressure behavior of iodine in the MOFs with similar port size and chemistry illustrates adaptations of the electronic structure of iodine to channel topology and strength of the iodine···framework interaction, which can be used to tailor iodine-immobilizing MOFs.