Effects of Funneliformis mosseae on Growth and Photosynthetic Characteristics of Camellia oleifera under Different Nitrogen Forms.

Nitrogen fertilizer increases agricultural yields but increases economic costs and causes a series of environmental problems. Arbuscular mycorrhizal fungi (AMF) have the potential to be used as biological fertilizer. However, the influence of nitrogen form on plant growth responsiveness to AMF inoculation is poorly understood. In this study, we investigated the effects of Funneliformis mosseae on growth, root morphology and photosynthetic characteristics of Camellia oleifera under different nitrogen forms during three harvest periods and clarified the most suitable nitrogen form for C. oleifera-AMF symbiosis. The results showed that urea, ammonium and nitrate nitrogen promoted plant growth and photosynthetic capacity, among which urea treatment had the highest value in all three harvests. No significant difference in plant growth parameters was observed between ammonium and nitrate nitrogen treatments in the first two harvests, while the plant height was significantly lower under ammonium nitrogen treatment than nitrate nitrogen treatment in the third harvest. Inoculation with F. mosseae in the presence of indigenous AMF could promote AMF colonization and plant growth at all three harvest times. Inoculation with F. mosseae significantly increased gas exchange parameters, the maximum photochemical efficiency (Fv/Fm) and the actual photochemical efficiency (ΦPSII). Inoculation with AMF increased the photochemical quenching coefficient (qP) better under urea treatment and improved the non-photochemical quenching coefficient (qN) better under ammonium nitrogen treatment. Principal component analysis showed that urea is the most beneficial nitrogen fertilizer for C. oleifera-AMF symbiosis. The results of this study provide a theoretical basis for the combination use of AMF and nitrogen fertilizer in agroforestry.

Fabrication of γ-Al2O3 Nanoarrays on Aluminum Foam Assisted by Hydroxide for Monolith Catalysts.

Heat distribution and good adhesion of the washcoat on monolith catalysts are critical to improving catalytic activity and long-term stability. Compared with cordierite, metal foam presents a high thermal conductivity coefficient. Also, the availability of "washcoat" in situ grown on metal substrates opens the door to eliminating the problem of coating peeling. Generally, hydrothermal or thermal methods are used for the fabrication of in situ grown washcoat on metal substrates. In this research, the aluminum foam monolith vertically aligned Al2O3 nanowire array is successfully prepared at ambient temperature in an alkaline solution for the first time. Furthermore, the Pt-loaded Al2O3 nanowire array (0.5 gPt/L monolith) is applied to C2H4 degradation. The catalyst converts 90% C2H4 at 147 °C with a gas hourly space velocity (GHSV) of 20,000 h-1. And a little decrease (1%) is observed in catalytic activity, even in 15 vol % water vapors. The catalysts show good thermal stability and water resistance property over 36 h at 300 °C. Above all, this study presents a simple way of in situ growth of washcoat on metal-substrate monolith with potentially scaled manufacturing. And the monolith catalyst shows good catalytic performance on C2H4, which can be applied for volatile organic compound treatment.

Corrigendum: Influence of carrier effect on Pd/Al2O3 for methane complete catalytic oxidation.

[This corrects the article DOI: 10.3389/fchem.2022.978698.].

Influence of carrier effect on Pd/Al2O3 for methane complete catalytic oxidation.

Pd/Al2O3 catalysts modified by different chemical elements (Mg, Si, Ce, and Zr) were tested for methane (CH4) catalytic combustion, and PdO nanoparticles loaded on modified Al2O3 were systematically studied. These conditions assess the carrier effects of Pd/Al2O3 and acid strength influences on CH4 combustion. We observed carrier effects on activation energy through tuning Pd 3d binding energies (BEs) and on pre-exponential factors (A) through Pd dispersion and acidity on supports. When the BE of Pd 3d5/2 is 337.3 eV, PdO nanoparticles loaded on modified Al2O3 have excellent activity in cracking the C-H bond of CH4, which leads to the lowest activation energy (E a ), regardless of the size effect of the PdO nanoparticle. Furthermore, a theoretical construction that acid sites on catalysts promote the reversible elementary step (2Pd-OH ↔ Pd-O* + Pd* + H2O) right shifts improving the A dependency on the quantity of exposed Pd* and Pd-O*. As a result, Al2O3, as the carrier, not only modifies the electronic characteristics and size of supported PdO nanoparticles but also participates in the reaction process via acid sites on the surface of Al2O3.

Aluminium-induced component engineering of mesoporous composite materials for low-temperature NH3-SCR.

Supported Mn2O3 is useful in achieving high dinitrogen selectivity at low temperature during ammonia-selective catalytic reduction (SCR). However, its controlled synthesis is challenging when the supporting material is the conventional pure silicon SBA-15 mesoporous molecular sieve. Here we show that silicon and aluminium in fly ash, the solid waste produced by coal-fired power plants, can be used to synthesize an Al-SBA-15 mesoporous molecular sieve support, which can guide the growth of Mn2O3 in the as-synthesized Fe-Mn/Al-SBA-15 NH3-SCR catalyst. Its superior catalytic performance is demonstrated by the high NOx conversion (≥90%) and selectivity (≥86%) at low temperatures (150-300 °C). The combined theoretical and experimental results reveal that the introduction of Al induces the growth of Mn2O3 catalysts. Our findings, therefore, provide a strategy for the rational design of low-temperature NH3-SCR catalysts through dopant-induced component engineering of composite materials.

VxMn(4-x)Mo3Ce3/Ti catalysts for selective catalytic reduction of NO by NH3.

A series of vanadium based catalysts (VxMn(4-x)Mo3Ce3/Ti) with different vanadium (x wt.%) and manganese ((4-x) wt.%) contents have been prepared by the wet impregnation method and investigated for selective catalytic reduction (SCR) of NOx by NH3 in the presence of 8 vol.% H2O and 500 ppmV SO2. The physicochemical characteristics of the catalysts were thoroughly characterized. The SCR of NOx by NH3 (NH3-SCR) activity, especially the low-temperature activity, significantly increased with increasing V2O5 content in the catalyst until the V2O5 content reached 1.5 wt.%, which corresponds well with the redox properties of the catalyst. All of the metal oxides were well dispersed and strongly interacted with each other on the catalyst surface. V mainly exists in the V5+ state in the catalysts. The strong synergistic effect between the vanadium and cerium species led to formation of more Ce3+ species, and that between the vanadium and manganese species contributed to formation of more manganese species with low valences. All of the catalysts exhibited strong acidity, while the redox properties determined the NH3-SCR activity, especially the low-temperature activity. H2O and SO2 had severe inhibiting effects on the activity of V1.5Mn2.5Mo3Ce3/Ti. However, good H2O and SO2 resistance and high NOx conversion by V1.5Mn2.5Mo3Ce3/Ti could be achieved in the presence of SO2 and almost no decline was observed in a long-term test at 275°C for 168 hr in the presence of SO2 and H2O, which can be attributed to the sulfate species formed on the catalyst surface.

CuO modified vanadium-based SCR catalysts for Hg0 oxidation and NO reduction.

The catalytic performance of Hg0 oxidation over vanadium-based SCR catalysts modified by different addition amounts of CuO was investigated. All catalysts were prepared by impregnation method and characterized. The 7% Cu/VWTi exhibited high Hg0 oxidation as well as a desired NO removal efficiency at 280-360 °C. The characterization revealed the enhancement of redox properties and well-dispersed active species results in the high catalytic performance after modification. The incorporation model showed that CuO in 7% Cu/VWTi was present in the monolayer dispersion, leading to the highest performance. Moreover, the effects of O2, NO, SO2, NH3 and HCl were explored. It showed all flue gas except NH3 could promote Hg0 oxidation. Fortunately, the inhibiting effect of NH3 could be scavenged if the catalyst is installed at the downstream of the SCR reactor. In addition, the mechanism of Hg0 oxidation over Cu/VWTi was discussed.

Effects of WO(x) modification on the activity, adsorption and redox properties of CeO2 catalyst for NO(x) reduction with ammonia.

A series of WO3/CeO2 (WO(x)/CeO2) catalysts were synthesized by wet impregnation of ammonium metatungstate on a CeO2 support. The resulting solid acid catalysts were characterized by X-ray diffraction (XRD), UV-Vis spectroscopy (UV-Vis), Raman spectroscopy (Raman), in-situ Fourier transform infrared spectroscopy (in-situ FT-IR) of ammonia adsorption, NH3-TPD, H2 temperature-programmed reduction (H2-TPR), NH3/NO oxidation and activity measurements for NO(x) reduction by NH3 (NH3-SCR). The results show that polytungstate (WO(x)) species are the main species of tungsten oxide on the surface of ceria. The addition of tungsten oxide enhances the Brönsted acidity of ceria catalysts remarkably and decreases the amount of surface oxygen on ceria, with strong interaction between CeO2 and WO(x). As a result, the N2 selectivity of NH3 oxidation and NH3-SCR at high temperatures (> 300 degrees C) is enhanced. Therefore, a wide working temperature window in which NO(x) conversion exceeds 80% (NO(x) conversion > 80%) from 200 to 450 degrees C, is achieved over 10 wt.% WO(x)/CeO2 catalyst. A tentative model of the NH3-SCR reaction route on WO(x)/CeO2 catalysts is presented.