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Methanol steam reforming is considered as a potential hydrogen supply pathway, and Cu-based catalysts are commonly used catalysts for this reaction. A series of CZAT-x catalysts were synthesized, which are derived from Cu/ZnO/Al2O3 catalysts by modifying the method of introducing TiO2 in this study. Characterization techniques (BET, XRF, XRD, H2-TPR, N2O chemisorption, TEM, and XPS) revealed that the mode of TiO2 introduction primarily influences surface Cu dispersion, reducibility and Cu–Ti interaction, subsequently affecting CZAT-x catalysts' catalytic activity and thermal stability in methanol steam reforming. The TiO2-doped catalyst prepared through solvent-assisted ball milling demonstrated the highest activity. The complete conversion of methanol could be achieved under the conditions of a water-to-methanol ratio of 1.2 and a reaction temperature of 493 K, and the H2 time-space yield could reach 103.9 mol kg−1 h−1. Furthermore, even after 10 h of thermal treatment test at 723 K, the CZAT-EA catalyst maintained a high methanol conversion rate. [ABSTRACT FROM AUTHOR]

The effects of long-term film mulching and primary nitrogen (N) fertilization strategies on the microbial processes underlying N2O emissions from calcareous upland soils are poorly understood. A two-year field experiment including five treatments viz. no mulching with recommended N (N225), film mulching with recommended N (F225), high dose N (F380), manure addition (F225+M), and no N (F0) was conducted to explore the N2O production pathways in a maize (Zea mays L.) cultivation system using combined isotopocule and quantitative PCR analysis. The cumulative N2O emissions were 0.56 − 0.68, 0.70 − 0.71, 1.06 − 1.07, 1.50 − 1.54, and 0.16 − 0.19 kg N2O-N ha−1 in N225, F225, F380, F225+M and F0 treatments, respectively. Nitrifier denitrification and/or classical denitrification accounted for 53.4 − 85.0% of the total N2O emissions in the high N2O emission period. Long-term film mulching changed the N2O-related community composition and led to a significantly higher fraction of bacterial denitrification and/or nitrifier denitrification (fdenitrification) in most events, compared with those in bare land. A relatively low fdenitrification and high N2O/(N2O + N2) ratio often occurred in the F225+M (in mixing-reduction scenario) and F380 treatments. Correlation analysis suggested that N2O fluxes were positively correlated with NO3−-N, dissolved organic N, total N, soil temperature, soil organic carbon, and the abundance of AOB amoA and nosZ genes, whereas they were negatively correlated with soil pH and C/N. Overall, our results suggest that long-term film mulching and N fertlization strategies could impact the processes of N2O production and consumption, whereas denitrification was still the primary N2O production pathways. [ABSTRACT FROM AUTHOR]

A series of nanocrystalline CoOx catalysts were synthesized by a citric acid complexation strategy. The effects of C2–C5 diols (including ethylene glycol, 1,3-propanediol, 1,4-butanediol, and 1,5-pentadiol) on catalyst structure and propane combustion performance were investigated. The results showed that the structure of CoOx transformed from pure Co3O4 to mixed-phase CoO–Co3O4 with a larger surface area and smaller crystallite size after the introduction of diol compounds. Importantly, diol compounds effectively weaken the Co–O bond strength in nanocrystalline CoOx and enhance the activity of oxygen species, thus effectively degrading propane. Due to the weakest Co–O bond strength, excellent oxygen species activity, abundant oxygen vacancies, and the strongest redox ability, the catalyst prepared by adding 1,3-propanediol (Co-PDO) exhibited the best catalytic activity (T90 = 227 °C). Moreover, the increase in pore size, surface Co2+ and oxygen vacancy content of Co-PDO in the 40 h stability test can compensate for the loss of activity caused by the decrease in specific surface area, thereby maintaining stable catalytic activity. [ABSTRACT FROM AUTHOR]