Showing papers on "Selective reduction published in 2023"
TL;DR: In this paper , a promising artificial carbon cycle to combat the global climate crisis is presented, the accomplishment of which however, is strongly criticised due to its high computational complexity and its high energy consumption.
Abstract: Photocatalyic CO2 in the atmosphere to fuels and value-added chemicals has been a promising artificial carbon cycle to combat the global climate crisis, the accomplishment of which however is strongly...
2 citations
2 citations
TL;DR: In this article , a linear scaling relationship was developed to map the intrinsic reactivity of 3D transition metal pincer complexes to their activity and selectivity in CO2 hydrosilylation.
Abstract: The stepwise catalytic reduction of carbon dioxide (CO2) to formic acid, formaldehyde, and methanol opens non-fossil pathways to important platform chemicals. The present article aims at identifying molecular control parameters to steer the selectivity to the three distinct reduction levels using organometallic catalysts of earth-abundant first-row metals. A linear scaling relationship was developed to map the intrinsic reactivity of 3d transition metal pincer complexes to their activity and selectivity in CO2 hydrosilylation. The hydride affinity of the catalysts was used as a descriptor to predict activity/selectivity trends in a composite volcano picture, and the outstanding properties of cobalt complexes bearing bis(phosphino)triazine PNP-type pincer ligands to reach the three reduction levels selectively under different reaction conditions could thus be rationalized. The implications of the composite volcano picture were successfully experimentally validated with selected catalysts, and the challenging intermediate level of formaldehyde could be accessed in over 80% yield with the cobalt complex 6. The results underpin the potential of tandem computational-experimental approaches to propel catalyst design for CO2-based chemical transformations.
1 citations
TL;DR: Support substrates play important roles in the catalysis process as discussed by the authors, and they play an important role in catalysis processes, and support substrates are important for catalysis in general.
Abstract: Support substrates play important roles in the catalysis process.
1 citations
01 Jan 2023
TL;DR: In this paper , the authors demonstrate cobaloxime as a bio-inspired molecular platform for exclusive ammonia synthesis via electrocatalytic NO2- reduction (eNO2-RR), which attained 98.5% Faradic efficiency under close-to-neutral conditions.
Abstract: Herein, we demonstrate cobaloxime as a bio-inspired molecular platform for exclusive ammonia synthesis via electrocatalytic NO2- reduction (eNO2-RR), which attained 98.5% Faradic efficiency (FE) under close-to-neutral conditions. Mechanistic studies illustrated...
TL;DR: In this paper , the detailed mechanism for ruthenium-catalysed selective reduction of cardanol derivatives by transfer hydrogenation has been fully characterised at the B3PW91-D3/ECP2/PCM/B3Pw91-ECP1 level of density functional theory.
TL;DR: ZnO/SnO2 was designed and prepared for highly selective CO2 reduction for HCOOH as discussed by the authors , achieving a faraday efficiency of 93.8% and a yield of 0.16 mmol h−1 cm−2 at the potential of −1.05 V.
Abstract: ZnO/SnO2 was designed and prepared for highly selective CO2 reduction for HCOOH. A faraday efficiency (FE) of 93.8% and a yield of 0.16 mmol h−1 cm−2 were obtained at the potential of −1.05 V.
TL;DR: In this paper , a bimetallic IrRu/ZSM-5 catalyst was prepared for the selective catalytic reduction of NO by CO in the presence of O2 (5%) for the low-temperature treatment of exhaust gas.
Abstract: The development of efficient catalysts for the selective catalytic reduction of NO by CO (CO-SCR) in the presence of O2 is highly desirable for controlling the emission of toxic gases from tailpipes. Here, a bimetallic IrRu/ZSM-5 catalyst was prepared for the selective catalytic reduction of NO by CO in the presence of O2 (5%) for the low-temperature treatment of exhaust gas. IrRu/ZSM-5 afforded 90% NOx conversion in the range of 225-250 °C and maintained 90% NOx conversion after 12 h of reaction. Ru addition inhibited agglomeration of the Ir particles during the reduction process and provided more active sites for NO adsorption. Isotopic C13O tracing and in situ diffuse reflectance infrared Fourier-transform spectroscopy experiments were used to elucidate the CO-SCR mechanism in the absence or presence of O2. NCO could easily form on the surface of catalysts in the absence of O2, whereas NCO formation has been inhibited owing to the quick consumption of CO in the presence of O2. Moreover, some byproducts such as N2O and NO2 are generated in the presence of O2. Finally, a possible mechanism for CO-SCR under different conditions was proposed based on in situ experiments and physicochemical analyses.
TL;DR: In this paper , a chemo-selective partial reduction of polyacrylates was feasible by using the state-of-the-art reducing agent, diisobutyl-t-butoxyaluminum hydride (LDBBA), to afford polymer featuring acrolein segments without the direct use of LDBBA.
Abstract: In this research, a chemo-selective partial reduction of polyacrylates was feasible by using the state-of-the-art reducing agent, diisobutyl-t-butoxyaluminum hydride (LDBBA), to afford polymer featuring acrolein segments without the direct use...
TL;DR: In this paper , the effects of steaming treatment on the acidity and aluminum structure of ZSM-5 were systematically investigated by using different types of zeolite catalysts, and the relationships between the acid properties and the catalytic performance of the methanol-to-aromatics (MTA) reaction were also elucidated.
TL;DR: In this article , a kinetic model was developed to simulate the reaction process of the Fe-Cu/zeolite Socony Mobil-5 (ZSM-5) catalyst for selective catalytic reduction of NO x with NH 3 (NH 3 -SCR).
Abstract: In this paper, a kinetic model was developed to simulate the reaction process of the Fe-Cu/zeolite Socony Mobil-5 (ZSM-5) catalyst for selective catalytic reduction of NO x with NH 3 (NH 3 -SCR). The global kinetic modeling accounted for various reactions occurring in SCR, including NH 3 adsorption/ desorption, standard SCR, fast SCR, slow SCR, NH 3 oxidation, NO oxidation and N 2 O formation reactions. The denitrification experiments were performed in a flow reactor with a feed stream, and the model could accurately predict the steady state conversion of NO at the reactor outlet. The results showed that the Fe-Cu/ZSM-5 catalyst exhibited an excellent catalytic activity, a high N 2 selectivity and an extended operating-temperature window across all temperatures ranging from 70 to 600ºC. By analyzing the influencing factors of the denitrification reaction, the results showed the temperature window shifted to lower temperatures with the gas hourly space velocity (GHSV), molar ratio of NH 3 /NO (normalized stoichiometric ratio, NSR), molar ratio of NO 2 /NO x as well as NO inlet concentration, and the operating window could be broadened with an increase in the O 2 concentration; lower GHSVs promoted the N 2 O formation. Due to ZSM-5 being rich in oxygen, the Fe-Cu/ZSM-5 catalyst exhibited high catalytic activity even without O 2 . The research findings could provide insight into improving low temperature SCR reactivity of zeolite-based catalysts.
TL;DR: In this paper , p-nitrophenol (PNP) is an important pesticide intermediate, which is also a water pollutant that is extremely harmful to personal health, and it can be converted to p-aminophenol (PAP) through selective catalytic...
Abstract: p-Nitrophenol (PNP) is an important pesticide intermediate, which is also a water pollutant that is extremely harmful to personal health. It can be converted to p-aminophenol (PAP) through selective catalytic...
TL;DR: In this paper , a Fe-embedded N-doped carbon (Fe-N-C) was used in the selective catalytic reduction of P-nitrophenol (PNP) to reduce the toxicity of waste effluents from industry.
Abstract: The selective catalytic reduction of nitroaromatics towards aromatic amines under mild reaction condition is an important approach to reduce the toxicity of waste effluents from industry and afterwards utilize the product as important fine organic chemical raw materials. P-nitrophenol (PNP) is chosen as the probe molecule of nitroaromatics in this study. A Fe-embedded N-doped Carbon (Fe-N-C) catalyst prepared using ZIF-8 has been identified as a highly active, selective and stable catalyst in the selective catalytic reduction of PNP. The Fe-N-C catalyst is for the first time applied in PNP reduction and found to present 100% conversion and 100% product selectivity. A mechanism investigation has been carried out to conclude that in the PNP reduction on Fe-N-C, water acts as the main hydrogen provider and sodium borohydride is the electron donator. Furthermore, the Fe-N-C catalyst works well when it is applied in PNP degradation in real water samples, which further indicates its applicability in industrial wastewater treatment. This work offers a simple and useful strategy to design robust catalysts for the selective catalytic reduction of nitroaromatics.
TL;DR: In this article , the use of an air-stable cationic hemiboronic acid catalyst for the chemoselective reduction of enones is described, which can be performed under ambient conditions.
Abstract: The use of an air-stable cationic hemiboronic acid catalyst for the chemoselective reduction of enones is described. By changing the identity and stoichiometry of the silane reducing agent, either the conjugate reduction products or the fully reduced products can be obtained in high selectivity. In contrast to analogous reactions catalyzed by air- and moisture-sensitive borane catalysts, the hemiboronic acid catalyzed protocol can be performed under ambient conditions. Profiling studies revealed that global reduction proceeds via a rapid initial 1,4-addition, followed by ketone deoxygenation with a rate that is highly silane-dependent.