The catalytic conversion of ethanol into butanol is one of crucial reactions in biorefinery for the production of renewable fuels and chemicals. The development of highly durable non‐noble ...metal‐based catalysts is of great significance but poses big challenges. Herein, we prepared a series of NiAl‐hydrotalcite derived Cu/NiAlOx catalysts via the hydrothermal precipitation method. Cu addition to the system shows an enhanced reactivity in the continuous catalytic conversion of ethanol into butanol. The 0.75 %Cu/NiAlOx catalyst afford a sustained ethanol conversion of ∼35 % and butanol selectivity of ∼45 % within 1000 h at 250 °C, 3 MPa N2. Complementary characterization studies reveal that Cu addition into the catalysts could not only provide redox sites for facilitating the dehydrogenation/hydrogenation processes, but also modulate the base/acid property for suppressing the side reactions. The excellent stability might stem from the enhanced interaction between Cu and Ni species, as evidenced by EDX‐mapping and H2‐TPR. We believe this work will help to rational design and develop of high‐performing and durable non‐noble metal catalysts for ethanol coupling to higher alcohols.
Acid‐base catalysis: High performing and stable Cu/NiAlOx catalysts were developed for continuous catalytic conversion of ethanol into butanol, with sustained ethanol conversion of ∼35 % and butanol selectivity of ∼45 % for 1000 h. The induced strong interaction between Cu and Ni species under the redox conditions could prevent the agglomeration of Cu species and maintain the long‐term stability in the catalysis.
Quantum technology relies on the utilization of resources, like quantum coherence and entanglement, which allow quantum information and computation processing. This achievement is however jeopardized ...by the detrimental effects of the environment surrounding any quantum system, so that finding strategies to protect quantum resources is essential. Non-Markovian and structured environments are useful tools to this aim. Here we show how a simple environmental architecture made of two coupled lossy cavities enables a switch between Markovian and non-Markovian regimes for the dynamics of a qubit embedded in one of the cavity. Furthermore, qubit coherence can be indefinitely preserved if the cavity without qubit is perfect. We then focus on entanglement control of two independent qubits locally subject to such an engineered environment and discuss its feasibility in the framework of circuit quantum electrodynamics. With up-to-date experimental parameters, we show that our architecture allows entanglement lifetimes orders of magnitude longer than the spontaneous lifetime without local cavity couplings. This cavity-based architecture is straightforwardly extendable to many qubits for scalability.
Effects of MC4R variants in previous Chinese population studies were inconsistent. Gene-environment interactions might influence the effect of MC4R variants on obesity, which was still unclear. We ...performed the study to clarify the association of variants near MC4R gene with obesity-related phenotypes and gene-environment interactions in Chinese children and adolescents. Two common variants (rs12970134 and rs17782313) near MC4R were genotyped in 2179 children and adolescents aged 7-18 years in Beijing of China. Associations between the variants and obesity-related phenotypes together with gene-environment interactions were analyzed. The A-alleles of rs12970134 were nominally associated with risk of overweight/obesity (Odds Ratios (OR) = 1.21, 95%CI: 1.03-1.44, P = 0.025) and BMI (β = 0.33 kg/m2, 95%CI: 0.02-0.63, P = 0.025), respectively. The rs12970134 was also associated with HDL-C (β = -0.03mmol/L per A-allele, 95%CI: -0.05, -0.01, P = 0.013) independent of BMI. In the further analysis, we found the significant interaction of rs12970134 and physical activity/sedentary behaviors on BMI (Pinteraction = 0.043). The rs12970134 was found to be associated with BMI only in children with physical activity<1h/d and sedentary behaviors ≥2h/d (BMI: β = 1.27 kg/m2, 95%CI: 0.10-2.45, P = 0.034). The association was not detected in their counterparts with physical activity≥1h/d or sedentary behaviors <2h/d. We identified the effect of MC4R rs12970134 on overweight/obesity and BMI, and we also found physical activity and sedentary behaviors modified the association between the rs12970134 and BMI in Chinese children and adolescents.
Heterogeneous, metal, single‐site catalysts often exhibit higher catalytic performance than other catalysts because of their maximized atom efficiency of 100 %. Reported herein is a ...precoordination/solvothermal polymerization strategy to fabricate a stable mononuclear Pd‐metalized porous organic polymer catalyst (Pd@POP). Pd@POP was easy to use in regioselective organic reactions because the internal structure of this Pd@POP can be easily modified. The catalyst was used to solve the intractable regioselectivity problems of Heck reactions. Pd@POP‐9 can efficiently activate the ends of olefins, thereby leading to high selectivity for substitution at the external position. To understand the reason underlying the high selectivity and activity of the catalyst, the systemic characterization of Pd@POP‐9 and density‐functional theory calculations were conducted. This Heck reaction is the first to be catalyzed by a recyclable mononuclear metal catalyst with unprecedented catalytic activity and regioselectivity.
Pop around: Reported herein is a precoordination/solvothermal polymerization strategy to fabricate a stable atomically dispersed mononuclear Pd‐metalized N‐heterocyclic carbene doped porous organic polymer catalyst (Pd@POP). This Heck reaction of electronically unbiased alkenes is the first to be catalyzed by a recyclable catalyst (Pd@POP‐9) with unprecedented catalytic activity and regioselectivity.
Abstract Utilizing both the electric and magnetic fields to manipulate electron dynamics enables the external control of topological states. This study investigates the topological characteristics of ...a quasi-one-dimensional ladder lattice subjected to a time-periodic electric field and a constant magnetic field. The Floquet topological phases are determined in the high-frequency approximation. In the absence of a magnetic field ( φ = 0), the energy band diagram is modulated by the electric field parameter α / ℏ ω , leading to a topological phase transition when α / ℏ ω crosses the value of 1. When a magnetic field is present ( ϕ = π ), the topological phase transitions in the ladder model are influenced by both the electric field parameter α / ℏ ω and the perpendicular hopping t 0 , resulting in a diverse range of adjustable topological states. These discoveries offer promising prospects for the utilization of ladder lattice systems with externally modifiable topological properties.
The coherent interaction between quantum emitters and photonic modes in cavities underlies many of the current strategies aiming at generating and controlling photonic quantum states. A plasmonic ...nanocavity provides a powerful solution for reducing the effective mode volumes down to nanometre scale, but spatial control at the atomic scale of the coupling with a single molecular emitter is challenging. Here we demonstrate sub-nanometre spatial control over the coherent coupling between a single molecule and a plasmonic nanocavity in close proximity by monitoring the evolution of Fano lineshapes and photonic Lamb shifts in tunnelling electron-induced luminescence spectra. The evolution of the Fano dips allows the determination of the effective interaction distance of ∼1 nm, coupling strengths reaching ∼15 meV and a giant self-interaction induced photonic Lamb shift of up to ∼3 meV. These results open new pathways to control quantum interference and field-matter interaction at the nanoscale.
Abstract
An intrinsic topological metal (TM) state is found in the T-graphene, a monolayer with both the time-reversal symmetry and the four-fold symmetry. The state distinguishes itself by the ...nontrivial electric polarization from the ordinary metals and features with two local edge states in the corresponding nanoribbons. The TM state is confirmed as a transition state bridging the ordinary metal state and the topological insulator state when the relative neighboring hoppings change in the lattice. The topological nature is further verified by checking the robustness of transport property against randomly-introduced strong disorders. The fact that the multiple topological states indexed by different parameters coexist in such a practical system shows a broad prospect in versatile topological transport devices.
Abstract
In this work, we study effects of different types of system-reservoir interactions on work costs and operating regimes of thermal machines by considering a quantum system consisting of two ...subsystems embedded in both independent and common reservoirs. The model allows us to make a contrast between three configurations of system-reservoir interactions, namely, the three-body one, the two-body one with and without intrasystem interaction between two subsystems. After establishing general formulations of thermodynamics quantities, we derive specific forms of heat and work with respect to these three configurations based on a model with two coupled qubits. It is shown that both the amount and sign of work are closely related to ways of system-reservoir interactions, by which six types of operating regimes of machines are constructed for a given setting. We find that different modes of system-reservoir interactions lead to different numbers of operating regimes of machines on the one hand, and on the other hand machines of the same kinds can appear in different scenarios of system-reservoir interactions, but which one is superior over others relies on intervals of parameters. A possible implementation of the setup based on the platform of circuit quantum electrodynamics is discussed briefly. We then generalize the bipartite model to multipartite case and derive the corresponding formulations of thermodynamics quantities. Our results indicate that interacting manners of system-reservoir play an important role in modifying thermodynamics process and can thus be utilized in designing quantum thermal machines with requisite functions.
Vibronic coupling is a central issue in molecular spectroscopy. Here we investigate vibronic coupling within a single pentacene molecule in real space by imaging the spatial distribution of ...single-molecule electroluminescence via highly localized excitation of tunneling electrons in a controlled plasmonic junction. The observed two-spot orientation for certain vibronic-state imaging is found to be evidently different from the purely electronic 0-0 transition, rotated by 90°, which reflects the change in the transition dipole orientation from along the molecular short axis to the long axis. Such a change reveals the occurrence of strong vibronic coupling associated with a large Herzberg-Teller contribution, going beyond the conventional Franck-Condon picture. The emergence of large vibration-induced transition charges oscillating along the long axis is found to originate from the strong dynamic perturbation of the anti-symmetric vibration on those carbon atoms with large transition density populations during electronic transitions.
•Simultaneous ammonia and nitrate removal was achieved in one airlift reactor.•DNRA and sulfate reduction were inhibited by intermittent aeration treatment.•Denitrification rate was improved by ...aeration compared with anoxic condition.•Heterotrophic nitrification was considered a potential ammonia metabolic pathway.
In this study, an airlift inner-loop sequencing batch reactor using poly(butylene succinate) as the biofilm carrier and carbon source was operated under an alternant aerobic/anoxic strategy for nitrogen removal in recirculating aquaculture system. The average TAN and nitrate removal rates of 47.35±15.62gNH4–Nm−3d−1 and 0.64±0.14kgNO3–Nm−3d−1 were achieved with no obvious nitrite accumulation (0.70±0.76mg/L) and the dissolved organic carbon in effluents was maintained at 148.38±39.06mg/L. Besides, the activities of dissimilatory nitrate reduction to ammonium and sulfate reduction activities were successfully inhibited. The proteome KEGG analysis illustrated that ammonia might be removed through heterotrophic nitrification, while the activities of nitrate and nitrite reductases were enhanced through aeration treatment. The microbial community analysis revealed that denitrifiers of Azoarcus and Simplicispira occupied the dominate abundance which accounted for the high nitrate removal performance. Overall, this study broadened our understanding of simultaneous nitrification and denitrification using biodegradable material as biofilm carrier.
PDF
