Formaldehyde is emitted from building and furnishing materials and consumer products, [1] and is known to cause irritation of eyes and respiratory tract, headache, pneumonia, and even cancer. [2,3] It is a dominant indoor air pollutant, especially in developing countries, and significant efforts have gone into indoor HCHO purification to meet environmental regulations and human health needs.Removal of HCHO by adsorbents has been investigated extensively using potassium permanganate, activated carbon, aluminum oxide, and some ceramic materials. [4][5][6] Sorbent effectiveness is typically limited by low adsorption capacities. Catalytic oxidation is the most effective technology for volatile organic compound (VOC) abatement because VOCs can be oxidized to CO 2 over certain catalysts at much lower temperatures than in thermal oxidation. [7][8][9] Supported noble metal catalysts (Pt, Pd, Rh, Au, Ag) or metal oxide catalysts (Ni, Cu, Cr, Mn) have been used for the catalytic oxidation of VOCs. [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] Complete oxidation of HCHO over catalysts occurs above 150 8C on clean and oxidized films of Ni, Pd, and Al [15] and over silver-cerium composite oxide, [16] above 100 8C over Ag/MnOx-CeO 2 [18] and Au/CeO 2 , [19] and above 85 8C over Pd-Mn/Al 2 O 3[17] and Au/FeOx. [20] As catalytic oxidation at even lower temperatures is desirable for indoor air purification, the development of a catalyst for total HCHO oxidation at room temperature is of great interest. In our recent study, [21,22] 1 % Pt/TiO 2 catalyst was shown to be effective for HCHO oxidation at room temperature, achieving 100 % conversion of d = 100 ppm HCHO to CO 2 and H 2 O at a gas hourly space velocity (GHSV) of 50 000 h À1 . However, we also observed that this type catalyst is not as active as needed for practical applications, and deactivates with time-on-stream.Herein, we report a novel alkali-metal-promoted Pt/TiO 2 catalyst for the ambient destruction of HCHO. We show that the addition of alkali-metal ions (such as Li + , Na + , and K + ) to Pt/TiO 2 catalyst stabilized an atomically dispersed Pt-O(OH)x-alkali-metal species on the catalyst surface and also opened a new low-temperature reaction pathway, significantly promoting the activity for the HCHO oxidation by activating H 2 O and catalyzing the facile reaction between surface OH and formate species to total oxidation products.Figure 1 a shows the HCHO conversion to CO 2 as a function of temperature over the x % Na-1 % Pt/TiO 2 (x = 0, 1, and 2) samples at a GHSV of 120 000 h À1 and HCHO inlet of d = 600 ppm. All gas streams were humidified to a RH of around 50 %. Before each activity test, the samples were reduced in H 2 at 300 8C for 30 min. The sodium-free catalyst had low activity for the HCHO oxidation reaction, with HCHO conversion being only about 19 % at 15 8C. With 1 % Na addition, the HCHO conversion reached 96 % at 15 8C and 100 % at 40 8C. With 2 % Na addition, 100 % HCHO conversion to CO 2 and H 2 O was measured at 15 8C. The effect of ...

CD4+ Th1 cells play a critical role in the induction of cell-mediated immune responses that are important for the eradication of intracellular pathogens. Peptide-25 is the major Th1 epitope for Ag85B of Mycobacterium tuberculosis and is immunogenic in I-Ab mice. To elucidate the role of the TCR and IFN-gamma/IL-12 signals in Th1 induction, we generated TCR transgenic mice (P25 TCR-Tg) expressing TCR alpha- and beta-chains of Peptide-25-reactive cloned T cells and analyzed Th1 development of CD4+ T cells from P25 TCR-Tg. Naive CD4+ T cells from P25 TCR-Tg differentiate into both Th1 and Th2 cells upon stimulation with anti-CD3. Naive CD4+ T cells from P25 TCR-Tg preferentially develop Th1 cells upon Peptide-25 stimulation in the presence of I-Ab splenic antigen-presenting cells under neutral conditions. In contrast, a mutant of Peptide-25 can induce solely Th2 differentiation. Peptide-25-induced Th1 differentiation is observed even in the presence of anti-IFN-gamma and anti-IL-12. Furthermore, naive CD4+ T cells from STAT1 deficient P25 TCR-Tg also differentiate into Th1 cells upon Peptide-25 stimulation. Moreover, Peptide-25-loaded I-Ab-transfected Chinese hamster ovary cells induce Th1 differentiation of naive CD4+ T cells from P25 TCR-Tg in the absence of IFN-gamma or IL-12. These results imply that interaction between Peptide-25/I-Ab and TCR may primarily influence determination of the fate of naive CD4+ T cells in their differentiation towards the Th1 subset.

Formaldehyde is emitted from building and furnishing materials and consumer products, [1] and is known to cause irritation of eyes and respiratory tract, headache, pneumonia, and even cancer. [2,3] It is a dominant indoor air pollutant, especially in developing countries, and significant efforts have gone into indoor HCHO purification to meet environmental regulations and human health needs.Removal of HCHO by adsorbents has been investigated extensively using potassium permanganate, activated carbon, aluminum oxide, and some ceramic materials. [4][5][6] Sorbent effectiveness is typically limited by low adsorption capacities. Catalytic oxidation is the most effective technology for volatile organic compound (VOC) abatement because VOCs can be oxidized to CO 2 over certain catalysts at much lower temperatures than in thermal oxidation. [7][8][9] Supported noble metal catalysts (Pt, Pd, Rh, Au, Ag) or metal oxide catalysts (Ni, Cu, Cr, Mn) have been used for the catalytic oxidation of VOCs. [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] Complete oxidation of HCHO over catalysts occurs above 150 8C on clean and oxidized films of Ni, Pd, and Al [15] and over silver-cerium composite oxide, [16] above 100 8C over Ag/MnOx-CeO 2[18] and Au/CeO 2 , [19] and above 85 8C over Pd-Mn/Al 2 O 3[17] and Au/FeOx. [20] As catalytic oxidation at even lower temperatures is desirable for indoor air purification, the development of a catalyst for total HCHO oxidation at room temperature is of great interest. In our recent study, [21,22] 1 % Pt/TiO 2 catalyst was shown to be effective for HCHO oxidation at room temperature, achieving 100 % conversion of d = 100 ppm HCHO to CO 2 and H 2 O at a gas hourly space velocity (GHSV) of 50 000 h À1 . However, we also observed that this type catalyst is not as active as needed for practical applications, and deactivates with time-on-stream.Herein, we report a novel alkali-metal-promoted Pt/TiO 2 catalyst for the ambient destruction of HCHO. We show that the addition of alkali-metal ions (such as Li + , Na + , and K + ) to Pt/TiO 2 catalyst stabilized an atomically dispersed Pt-O(OH)x-alkali-metal species on the catalyst surface and also opened a new low-temperature reaction pathway, significantly promoting the activity for the HCHO oxidation by activating H 2 O and catalyzing the facile reaction between surface OH and formate species to total oxidation products. Figure 1 a shows the HCHO conversion to CO 2 as a function of temperature over the x % Na-1 % Pt/TiO 2 (x = 0, 1, and 2) samples at a GHSV of 120 000 h À1 and HCHO inlet of d = 600 ppm. All gas streams were humidified to a RH of around 50 %. Before each activity test, the samples were reduced in H 2 at 300 8C for 30 min. The sodium-free catalyst had low activity for the HCHO oxidation reaction, with HCHO conversion being only about 19 % at 15 8C. With 1 % Na addition, the HCHO conversion reached 96 % at 15 8C and 100 % at 40 8C. With 2 % Na addition, 100 % HCHO conversion to CO 2 and H 2 O was measured at 15 8C. The effect of ...

We used STM to observe visible light photo-oxidation reactions of formic acid on the ordered lattice-work structure of a TiO(2)(001) surface for the first time. The nanostructured surface makes the band gap significantly smaller than 3.0 eV only at the surface layer, and the surface state of the crystal enables a visible light response.

The transfer hydrogenolysis of glycerol promoted by supported palladium catalysts is reported. The reactions were carried out under mild conditions (453 K and 5 bar of N 2 ) in absence of added hydrogen by using the reaction solvent, 2-propanol, as hydrogen source. The catalytic results are interpreted in terms of metal (Pd) -metal (Co or Fe) interaction that modifies the electronic properties of palladium and affords bimetallic PdM sites (M = Co or Fe), thus enhancing the catalytic properties of the systems in the conversion of glycerol as well as in the selectivity to 1,2-propanediol and 1-propanol. The transfer hydrogenolysis mechanism is here elucidated and involves the glycerol dehydration to 1-hydroxyacetone and the subsequent hydrogenation of 1-hydroxyacetone to propylene glycol.3

No abstract

Experimental details Catalyst preparationThe SBA-15 supported CuAu nanocatalyst was prepared using a modification of the two-step approach described in literature.1,2 Typically, before the preparation of catalysts, the surface of the support SBA-15 was first functionalized with APTES (H 2 N(CH 2 ) 3 Si(OEt) 3 ) so as to prepare SBA-15 supported gold-copper alloy nanoparticles. Briefly, 1.0 g SBA-15 and 2.5 g APTES were dissolved into 50 ml ethanol, followed by reflux for 24 h. After filtration, washing and drying, the functionalized SBA-15 was obtained and denoted as NH 2 -SBA-15.After that, the NH 2 -SBA-15 support was dissolved in a defined amount of tetrachloroaurate (HAuCl 4 ) solution followed by reduction with NaBH 4 . After continuous stirring at room temperature for 30 min, and then filtration and washing, the obtained solid was added to the 50 ml of copper nitrate (Cu(NO 3 ) 2 ) solution. The mixture was again reduced by NaBH 4, followed by continuously stirring, filtration and thorough washing. The discovered solid was calcined at 873 K in air for 6 h to get catalyst precursor, and then reduced at 623 K in 5% H 2 -95% N 2 atmosphere for 4 h to obtain the CuAu x /SBA-15 (where x denotes atomic radio ofAu to Cu) catalysts. In the synthesis, the Cu loading was kept constant at 6 wt% and the Au/Cu atomic ratio was varied accordingly.

Carbon nanotube-supported RuFe bimetallic catalysts (RuFe/CNT) were prepared through a coimpregnation method for the selective hydrogenolysis of 20 wt % glycerol aqueous solution to produce glycols (1,2-propanediol and ethylene glycol). The Ru/CNT catalyst with smaller Ru nanoparticles (NPs) was significantly active for C-C bond cleavage, giving a considerable amount of CH(4) in the hydrogenolysis product. The RuFe/CNT catalyst with bimetallic NPs having an average size similar to Ru/CNT was more efficient for C-O bond cleavage, affording higher selectivity to glycols. Almost 100% glycerol conversion and over 75% selectivity to glycol could be obtained using the optimized RuFe/CNT catalyst under relatively mild conditions. The bimetallic RuFe/CNT catalyst was structurally robust and showed excellent reusability. Transmission electron microscopic images revealed that, when an appropriate amount of Fe entity was added, the RuFe bimetallic NPs were uniformly dispersed on the CNT surfaces and had an average size of similar to 3 nm. X-ray photoelectron spectroscopy indicated that a portion of the Fe species were interacted with Ru moieties, forming Ru-Fe alloys on the Ru domain, whereas other Fe species were in the forms of iron oxides, likely FeO and FeO(1+x) (0 < x < 0.5), mostly presenting on the periphery of RuFe bimetallic NPs. The occurrence of iron oxide species is crucial for the stability of RuFe bimetallic NPs during catalytic runs; but excess iron oxides block the surfaces of RuFe bimetallic NPs, resulting in a decrease in catalytic activity. Higher performance of the RuFe/CNT catalyst is attributed to the synergistic effects of the formation of Ru-Fe alloys and the interactions between the RuFe bimetallic NPs and iron oxides on CNT surfaces.National Basic Research Program of China[2011CBA00508]; National Natural Science Foundation of China[20873108, 20923004]; Program for Changjiang Scholars and Innovative Research Team in University[IRT1036]; Catalysis Research Center, Hokkaido University[10B0043]; Japan Society for the Promotion of Science (JSPS