Methane activation by laser-ablated Th atoms on the triplet potential energy surface produces the methylthorium hydride, CH3-Th-H, that converts smoothly by α-H transfer to CH2-ThH2, which relaxes in the matrix to the more stable singlet methylidene, CH2═ThH2. This first actinide methylidene was characterized from argon matrix infrared spectra and B3LYP calculations in our laboratory. We now report neon matrix investigations, which include the methylthorium hydride and the Th-D stretching modes of CD2═ThD2 that are blue-shifted in neon from under the intense CD4 precursor absorption, and reactions with CH2D2 that give rise to the CHD═ThHD modifications and their α-H and α-D transfer counterparts CD2═ThH2 and CH2═ThD2. New intrinsic reaction coordinate calculations show that this reaction proceeds smoothly on the triplet potential energy surface.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1021/jp506282n | DOI Listing |
Chem Sci
January 2025
Department of Chemistry, Indian Institute of Technology Hauz Khas Delhi New Delhi 110016 India
The direct transformation of methane into C oxygenates such as acetic acid selectively using molecular oxygen (O) is a significant challenge due to the chemical inertness of methane, the difficulty of methane C-H bond activation/C-C bond coupling and the thermodynamically favored over-oxidation. In this study, we have successfully developed a porous aluminium metal-organic framework (MOF)-supported single-site mono-copper(ii) hydroxyl catalyst [MIL-53(Al)-Cu(OH)], which is efficient in directly oxidizing methane to acetic acid in water at 175 °C with a remarkable selectivity using only O. This heterogeneous catalyst achieved an exceptional acetic acid productivity of 11 796 mmol mol h in 9.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
South China University of Technology, School of Chemistry and Chemical Engineering, Wushan St., 510640, Guangzhou, CHINA.
An inevitable overoxidation process is considered as one of the most challenging problems in the direct conversion of methane (CH4) to methanol (CH3OH), which is limited by the uncontrollable cracking of key intermediates. Herein, we have successfully constructed a photocatalyst, the Fe-doped ZnO hollow polyhedron (Fe/ZnOHP), for the highly selective photoconversion of CH4 to CH3OH under mild conditions. In-situ experiments and density functional theory calculations confirmed that the introduction of Fe was able to decrease the energy level of the O 2p orbital, which passivated the activity of lattice oxygen in ZnO nanocrystals.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
Department of Chemical Engineering, Northeastern University, Boston, Massachusetts, 02115, USA.
Discovering electrocatalysts that can efficiently convert carbon dioxide (CO) to valuable fuels and feedstocks using excess renewable electricity is an emergent carbon-neutral technology. A single metal atom embedded in doped graphene, , single-atom catalyst (SAC), possesses high activity and selectivity for electrochemical CO reduction (COR) to CO, yet further reduction to hydrocarbons is challenging. Here, using density functional theory calculations, we investigate stability and reactivity of a broad SAC chemical space with various metal centers (3d transition metals) and dopants (2p dopants of B, N, O; 3p dopants of P, S) as electrocatalysts for COR to methane and methanol.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
UESTC: University of Electronic Science and Technology of China, School of Materials and Energy, Chengdu, Sichuan, 611731, Chengdu, CHINA.
The electrochemical reduction of carbon dioxide (CO2) to methane (CH4) presents a promising solution for mitigating CO2 emissions while producing valuable chemical feedstocks. Although single-atom catalysts have shown potential in selectively converting CO2 to CH4, their limited active sites often hinder the realization of high current densities, posing a selectivity-activity dilemma. In this study, we developed a single-atom cobalt (Co) doped copper catalyst (Co1Cu) that achieved a CH4 Faradaic efficiency exceeding 60% with a partial current density of -482.
View Article and Find Full Text PDFChem Commun (Camb)
January 2025
School of Materials Science and Engineering, Shandong University of Science and Technology, Qingdao 266590, China.
The catalysts of Ni nanoparticles supported on ZrO, LaO and LaZrO were prepared and employed in photothermal catalytic DRM. High yield of H and CO (76.2 and 99.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!