The aerobic, selective oxidation of methane to C -oxygenates remains a challenge, due to the more facile, consecutive oxidation of formed products to CO . Here, we report on the aerobic selective oxidation of methane under continuous flow conditions, over platinum-based catalysts yielding formaldehyde with a high selectivity (reaching 90 % for Pt/TiO and 65 % over Pt/Al O ) upon co-feeding water. The presence of liquid water under reaction conditions increases the activity strongly attaining a methane conversion of 1-3 % over Pt/TiO . Density-functional theory (DFT) calculations show that the preferential formation of formaldehyde is linked to the stability of the di-σ-hydroxy-methoxy species on platinum, the preferred carbon-containing species on Pt(111) at a high chemical potential of water. Our findings provide novel insights into the reaction pathway for the Pt-catalysed, aerobic selective oxidation of CH .
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC9541881 | PMC |
http://dx.doi.org/10.1002/anie.202206841 | DOI Listing |
Nanoscale Adv
January 2025
Faculty of Chemical and Food Technology, Ho Chi Minh City University of Technology and Education 01 Vo Van Ngan Street, Linh Chieu Ward, Thu Duc City Ho Chi Minh City 700000 Vietnam
Photocatalytic methane oxidation under mild conditions using single-atom catalysts remains an advanced technology. In this work, gold single atoms (Au SAs) were introduced onto TiO nanostructures using a simple method. The resulting performance demonstrated effective conversion of methane into H and C products at room temperature.
View Article and Find Full Text PDFLaser absorption spectroscopy (LAS) is a well-established measurement technique for quantitative chemical speciation in a combustion environment. However, LAS measurement of nitric oxide (NO) in ammonia flames has never been reported in the literature. This is despite the community's recent strong interest in carbon-neutral ammonia combustion and the associated NO formation problem.
View Article and Find Full Text PDFFlow Turbul Combust
November 2024
Institut de Mécanique des Fluides de Toulouse, IMFT, CNRS, Université de Toulouse, Toulouse, France.
Improving mixing between two coaxial swirled jets is a subject of interest for the development of next generations of fuel injectors. This is particularly crucial for hydrogen injectors, where the separate introduction of fuel and oxidizer is preferred to mitigate the risk of flashback. Raman scattering is used to measure the mean compositions and to examine how mixing between fuel and air streams evolves along the axial direction in the near-field of the injector outlet.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Peking University Shenzhen Graduate School, Shool of Chemical Biology and Biotechnology, Lishui Road, Nanshan District, -, Shenzhen, CHINA.
Regulating the coordination environment of active sites has proved powerful for tapping into their catalytic activity and selectivity in homogeneous catalysis, yet the heterogeneous nature of copper single-atom catalysts (SACs) makes it challenging. This work reports a bottom-up approach to construct a SAC (rGO@Cu-N(Hx)-C) by inlaying preformed amine coordinated Cu2+ units into reduced graphene oxide (rGO), permitting molecular level revelation on how the proximal N-site functional groups (N-H or N-CH3) impact on the carbon dioxide reduction reaction (CO2RR). It is demonstrated that the N-H moiety of rGO@Cu-NHx-C can serve as an in-situ protonation agent to accelerate the CO2-to-methane reduction kinetics, delivering a methane current density (163 mA/cm2) 2.
View Article and Find Full Text PDFSci Rep
January 2025
College of Ecology and Environment, Hainan University, Haikou, 570228, China.
Agroforestry systems are known to enhance soil health and climate resilience, but their impact on greenhouse gas (GHG) emissions in rubber-based agroforestry systems across diverse configurations is not fully understood. Here, six representative rubber-based agroforestry systems (encompassing rubber trees intercropped with arboreal, shrub, and herbaceous species) were selected based on a preliminary investigation, including Hevea brasiliensis intercropping with Alpinia oxyphylla (AOM), Alpinia katsumadai (AKH), Coffea arabica (CAA), Theobroma cacao (TCA), Cinnamomum cassia (CCA), and Pandanus amaryllifolius (PAR), and a rubber monoculture as control (RM). Soil physicochemical properties, enzyme activities, and GHG emission characteristics were determined at 0-20 cm soil depth.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!