Abstract
Direct selective transformation of greenhouse methane (CH4) to liquid oxygenates (methanol) can substitute energy-intensive two-step (reforming/Fischer–Tropsch) synthesis while creating environmental benefits. The development of inexpensive, selective, and robust catalysts that enable room temperature conversion will decide the future of this technology. Single-atom catalysts (SACs) with isolated active centers embedded in support have displayed significant promises in catalysis to drive challenging reactions. Herein, high-density Ni single atoms are developed and stabilized on carbon nitride (NiCN) via thermal condensation of preorganized Ni-coordinated melem units. The physicochemical characterization of NiCN with various analytical techniques including HAADF-STEM and X-ray absorption fine structure (XAFS) validate the successful formation of Ni single atoms coordinated to the heptazine-constituted CN network. The presence of uniform catalytic sites improved visible absorption and carrier separation in densely populated NiCN SAC resulting in 100% selective photoconversion of (CH4) to methanol using H2O2 as an oxidant. The superior catalytic activity can be attributed to the generation of high oxidation (NiIII═O) sites and selective C─H bond cleavage to generate •CH3 radicals on Ni centers, which can combine with •OH radicals to generate CH3OH.
Original language | English |
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Article number | 2304574 |
Journal | Small |
Volume | 20 |
Issue number | 15 |
Early online date | 27 Nov 2023 |
DOIs | |
State | Published - 11 Apr 2024 |
Externally published | Yes |
Bibliographical note
Publisher Copyright:© 2023 The Authors. Small published by Wiley-VCH GmbH.
Funding
P.A., I.N. and S.K. acknowledges financial support from institutional sources of the Department of Inorganic Chemistry, Palacký University Olomouc, Czech Republic. Ondrej Tomanec, Ms. J. Stráská, and Martin Petr are acknowledged for the measurement of HRTEM, TEM, and XPS, respectively. J. Michalička and CzechNanoLab Research Infrastructure supported by MEYS CR (LM2023051) are also acknowledged for the TEM results. D. Milde is acknowledged for ICP‐MS analysis. P.K., J.H. and M.G.K. would like to thank the University of Calgary's Canada First Research Excellence Fund (CFREF) for financial assistance. The authors also acknowledge Canadian Light Source (project: 35G12344), a national research facility of the University of Saskatchewan, which is supported by the Canada Foundation for Innovation (CFI), the Natural Sciences and Engineering Research Council (NSERC), the National Research Council (NRC), the Canadian Institutes of Health Research (CIHR), the Government of Saskatchewan, and the University of Saskatchewan. Drs. Ning Chen, Adam Leontowich, Beatriz Diaz‐Moreno, Jay Dynes, Tom Regier, and Zachary Arthur are kindly acknowledged for XANES/EXAFS, WAXS, and soft X‐ray analysis on the samples.
Funders | Funder number |
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Department of Inorganic Chemistry | |
University of Calgary's Canada First Research Excellence Fund | |
Canadian Light Source | 35G12344 |
University of Saskatchewan | |
National Research Council | |
Government of Saskatchewan | |
Canadian Institutes of Health Research | |
Natural Sciences and Engineering Research Council of Canada | |
Canada Foundation for Innovation | |
Ministerstvo Školství, Mládeže a Tělovýchovy | LM2023051 |
Univerzita Palackého v Olomouci | |
Canada First Research Excellence Fund |
Keywords
- Ni single atom catalysts
- carbon nitride
- heterogeneous catalysts
- methane oxidation
- photocatalysis