NH 3 is not only the key chemical raw material for the industry but also a carbon-free fuel and mobile carrier of renewable energy in the future. So far, industrial NH 3 synthesis is still dominated by the traditional Haber-Bosch reaction, which requires high temperatures of 300-500 ºC and pressures of 200-300 atm. To overcome these shortcomings, Nanba et al. have designed the NO-CO-H 2 O reaction system. In this reaction, NO was used as the raw material and reduced to NH 3 by H 2 O and toxic gases CO. The reaction equation is as follows: NO + 2.5CO + 1.5H 2 O → NH 3 + 2.5CO 2 (ΔH 298.15K = -414.86 kJ·mol -1 ). Recently, our research found that the NO-CO-H 2 O reaction can be approximately decomposed into a series reaction of WGSR of CO-H 2 O and reduction of NO-H 2 .
When the incident photon frequency of incident light matches the vibration frequency of noble metal nanoparticles, the nanoparticles have strong absorption of photon energy and local surface plasmon resonance (LSPR) occurs. The metal with the LSPR effect can excite high-energy hot electrons and holes, which helps to activate the reactants, thus reducing the reaction energy and increasing the reaction rate. As a rare non-noble metal with an LSPR effect, Cu has been widely used in CO hydrogenation reactions.
Cu/CeO 2 was prepared by a simple wet impregnation method and the reactivity of NO reduction to NH 3 by CO in a photothermal synergistic system was studied. As expected, high activity was obtained over Cu/CeO 2 under visible light irradiation. The LSPR effect of Cu nanoparticles can increase the NH 3 yield under mild conditions.
Recently, a research team led by Prof. Wenxin Dai from Fuzhou University, China, reported a photothermal catalytic system comprising Cu/CeO 2 that was applied to the reaction between NO, CO and H 2 O for the production of NH 3 under visible-light irradiation. High NO conversion (94.4%) and NH 3 selectivity (66.5%) were achieved over Cu/CeO 2 in the presence of H 2 O at 210°C. Visible light further improved the conversion of NO (97.7%) and selectivity for NH 3 (69.1%). The quasi-situ EPR and in-situ DRIFTS results indicated that CO initially reacts with H 2 O to form an HCO 3 * intermediate, which then decomposes into CO 2 and activated H * . Finally, NO reacts with activated H * to produce NH 3 . The localized surface plasmon resonance effect of Cu nanoparticles induced by visible light promotes the decomposition of HCO 3 * to CO 2 and H * , while regenerating oxygen vacancies (OVs, H 2 O activation sites) at the CeO 2 sites, resulting in enhanced NH 3 production. The results were published in Chinese Journal of Catalysis (https://doi.org/10.1016/S1872-2067(23)64439-0).
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About the Journal
Chinese Journal of Catalysis is co-sponsored by Dalian Institute of Chemical Physics, Chinese Academy of Sciences and Chinese Chemical Society, and it is currently published by Elsevier group. This monthly journal publishes in English timely contributions of original and rigorously reviewed manuscripts covering all areas of catalysis. The journal publishes Reviews, Accounts, Communications, Articles, Highlights, Perspectives, and Viewpoints of highly scientific values that help understanding and defining of new concepts in both fundamental issues and practical applications of catalysis. Chinese Journal of Catalysis ranks at the top one journal in Applied Chemistry with a current SCI impact factor of 16.5. The Editors-in-Chief are Profs. Can Li and Tao Zhang.
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Chinese Journal of Catalysis