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TiO 2 supported catalysts have been widely studied for the selective catalytic reduction (SCR) of NO x ; however, comprehensive understanding of synergistic interactions in multi-component SCR catalysts is still lacking. Herein, transition metal elements (V, Cr, Mn, Fe, Co, Ni, Cu, La, and Ce) were loaded onto TiO 2 nanoarrays via ion-exchange using protonated titanate precursors. Amongst these catalysts, Mn-doped catalysts outperform the others with satisfactory NO conversion and N 2 selectivity. Cu co-doping into the Mn-based catalysts promotes their low-temperature activity by improving reducibility, enhancing surface Mn 4+ species and chemisorbed labile oxygen, and elevating the adsorption capacity of NH 3 and NO x species. While Ce co-doping with Mn prohibits the surface adsorption and formation of NH 3 and NO x derived species, it boosts the N 2 selectivity at high temperatures. By combining Cu and Ce as doping elements in the Mn-based catalysts, both the low-temperature activity and the high-temperature N 2 selectivity are enhanced, and the Langmuir–Hinshelwood reaction mechanism was proved to dominate in the trimetallic Cu–Ce–5Mn/TiO 2 catalysts due to the low energy barrier. 

Converting CO₂to value‐added chemicals,e. g., CH₃OH, is highly desirable in terms of the carbon cycling while reducing CO₂emission from fossil fuel combustion. Cu‐based nanocatalysts are among the most efficient for selective CO₂‐to‐CH₃OH transformation; this conversion, however, suffers from low reactivity especially in the thermodynamically favored low temperature range. We herein report ultrasmall copper (Cu) nanocatalysts supported on crystalline, mesoporous zinc oxide nanoplate (Cu@mZnO) with notable activity and selectivity of CO₂‐to‐CH₃OH in the low temperature range of 200–250 °C. Cu@mZnO nanoplates are prepared based on the crystal‐crystal transition of mixed Cu and Zn basic carbonates to mesoporous metal oxides and subsequent hydrogen reduction. Under the nanoconfinement of mesopores in crystalline ZnO frameworks, ultrasmall Cu nanoparticles with an average diameter of 2.5 nm are produced. Cu@mZnO catalysts have a peak CH₃OH formation rate of 1.13 mol h⁻¹per 1 kg under ambient pressure at 246 °C, about 25 °C lower as compared to that of the benchmark catalyst of Cu−Zn−Al oxides. Our new synthetic strategy sheds some valuable insights into the design of porous catalysts for the important conversion of CO₂‐to‐CH₃OH.

 

CO₂conversion into valuable chemicals and fuels, such as methanol, is one of the most practical routes for utilizing emitted CO₂and mitigating global warming. Herein, a 3D Cu‐decorated ZnO nanorod array based structured catalysts for efficient thermochemical CO₂hydrogenation to methanol at relatively low pressures (<10 atm) is successfully fabricated and demonstrated. This new type of nanorod array integrated structured catalysts has yielded a methanol formation rate of 1.9 mol h⁻¹kg⁻¹with a methanol selectivity of 56%, rivaling the state‐of‐the‐art powder‐form catalysts. The well‐dispersed copper species on the array structure as well as the array‐structure‐enhanced interfacial effect are key factors that improve the activity of the nanorod array catalysts in CO₂hydrogenation. The Cu‐ZnO nanorod array interface also suppresses reverse water‐gas shift reaction, reducing the selectivity to CO. Further improvement of the performance of the nanorod array based catalysts is demonstrated by tuning the ZnO nanorod array length. The developed nanorod array integrated monolithic catalysts also exhibit good stability during a long‐time continuous operation, demonstrating the potential and the feasibility of their practical implementation in industrial situation.