CO2 hydrogenation to methanol over Cu/CeO2 and Cu/ZrO2 catalysts:Tuning methanol selectivity via metal-support interaction

Copper-based catalysts for CO2 hydrogenation to methanol are supported on ZrO2 and CeO2,respectively.Reaction results at 3.0 MPa and temperatures between 200 and 300°C reveal that Cu catalysts supported on ZrO2 and CeO2 exhibit better activity and selectivity than pure Cu catalyst due to Cu-support(ZrO2 and CeO2)interaction.Combining the structural characterizations with in-situ diffuse reflectance infrared Fourier transform spectroscopy(in-situ DRIFTS),Cu/CeO2 shows the higher methanol selectivity due to the formation of main carbonates intermediates,which are closely related with the oxygen vacancies over Cu/CeO2.In contrast,bicarbonate and carboxyl species are observed on Cu/ZrO2,which originates from the hydroxyl groups presented on catalyst surfaces.Difference in CO2 adsorption intermediates results in the distinct methanol selectivity over the two catalysts.

An investigation of Zr/Ce ratio influencing the catalytic performance of CuO/Ce1-xZrxO2 catalyst for CO2 hydrogenation to CH3OH

A series of CuO/Ce1-xZrxO2 catalysts(x=0.2,0.4,0.6 and 0.8)are applied to elaborate the effect of the Zr/Ce ratio on the catalytic performance of CO2 hydrogenation to CH3OH.The best catalytic performance is achieved with CuO/Ce0.4Zr0.6O2,exhibiting XCO2=13.2%and YCH3OH=9.47%(T=280℃,P=3 MPa).The formation of dispersed surface CuO species and larger number of oxygen vacancies are detected over CuO/Ce0.4Zr0.6O2 due to stronger interaction between CuO and Ce0.4Zr0.6O2,resulting in the superior activation ability for H2 and CO2 respectively.Additionally,the evidence is provided by in situ DRIFTS under the activity test pressure(3 MPa)that bi/m-HCOO* species are preferable for accumulating over ceria-rich(CuO/Ce0.6Zr0.4O2 and CuO/Ce0.8Zr0.2O2)catalysts while zirconia-rich(CuO/Ce0.4Zr0.6O2 and CuO/Ce0.2Zr0.8O2)catalysts are benefit to encourage the transformation of bi/m-HCOO* species to CH3OH.The abundant population and high activity of intermediate species over CuO/Ce0.4Zr0.6O2 give a strong positive effect on the catalytic performance.

CO_(2)hydrogenation to methanol promoted by Cu and metastable tetragonal Ce_(x)Zr_(y)O_(z) interface

Designing effective catalyst to improve the activity of CO_(2) hydrogenation to methanol is a potential avenue to realize the utilization of CO_(2) resources. Herein we construct three kinds of Cu/Ce_(x)Zr_(y)O_(z)(CCZ) catalysts with different crystal phases of Ce_(x)Zr_(y)O_(z)solid solutions, which demonstrate distinct activity and methanol selectivity in the order of metastable tetragonal-CCZ(CCZ-t’’, parts of oxygen in Ce_(x)Zr_(y)O_(z) were replaced by tetragonal phase from cubic fluorite phase) > tetragonal-CCZ(CCZ-t) > cubic-CCZ(CCZ-c) for CO_(2) hydrogenation to methanol. Structural analysis reveals that oxygen vacancies, surface hydroxyls and unsaturated Cu species of CCZ all follow the same sequence as that of activity and methanol selectivity,indicating that the above features are beneficial to improve the catalytic reaction performance.Temperature programmed experiments and mechanism studies show that the interface between Cu and tetragonal(t and t’’) Ce_(x)Zr_(y)O_(z) can promote CO_(2) adsorption, and the adsorbed CO_(2) is more reactive and can generate active bidentate carbonate species, which can be hydrogenated to form active monodentate and bidentate formate species under CO_(2) and H_(2) atmosphere. These intermediates should be crucial to the formation of methanol product. CCZ-t’’has stronger H_(2) activation ability than CCZ-t, which makes the former catalyst have more intermediates and higher methanol selectivity. In contrast, CO_(2) mainly adsorbs on cubic Ce_(x)Zr_(y)O_(z) support of CCZ-c, but its H_(2) spillover ability is low, which hinders the reaction process. In addition, the strong adsorption of surface intermediates on CCZ-c is also not conducive to methanol formation. Results here demonstrate that constructing active Cu-support interfaces may be an important approach to design effective catalyst for CO_(2)hydrogenation.

Patient Participation in Communication about Treatment Decision-Making for Localized Prostate Cancer during Consultation Visits

Objectives: To describe the communication behaviors of patients and physicians and patient par-ticipation in communication about treatment decision-making during consultation visits for local-ized prostate cancer (LPCa). Methods: This is a secondary analysis of data from 52 men enrolled in the usual care control group of a randomized trial that focused on decision-making for newly diagnosed men with LPCa. We analyzed the patient-physician communication using the transcribed audio-recordings of real-time treatment consultations and a researcher-developed coding tool, including codes for communication behaviors (information giving, seeking, and clarifying/ verifying) and contents of clinical consultations (health histories, survival/mortality, treatment options, treatment impact, and treatment preferences). After qualitative content analysis, we categorized patient participation in communication about treatment-related clinical content, including “none” (content not discussed);“low” (patient listening only);“moderate” (patient providing information or asking questions);and “high” (patient providing information and asking questions). Results: Physicians mainly provided information during treatment decision consultations and patients frequently were not active participants in communication. The participation of patients with low and moderate cancer risk typically was: 1) “moderate and high” in discussing health histories;2) “low” in discussing survival/mortality;3) “low and moderate” in discussing treatment options;4) “none and low” in discussing treatment impacts;and 5) “low” in discussing treatment preferences. Conclusions: Findings suggest opportunities for increasing patient participation in communication about treatment decision-making for LPCa during clinical consultations.

A Full Dynamic Voltage Stability Research Based on Time-domain Simulation

The voltage stability is substantially a dynamic stability, but the primary method which is more mature and engineering practical to analyze the stability of voltage is still static analysis. The time-domain simulation is an important measure in research of complex power grid. With the development of full dynamic simulation technology, the research of dynamic voltage stability by using full dynamic simulation program which is based on time-domain simulation can be carried out. This paper uses full dynamic simulation program in dynamic voltage stability research, lays special stress on research in how generator over-excitation limiter functioned and influence in dynamic voltage stability research, and raise 2 methods and steps to figure out dynamic stable voltage in both over-excitation counted and not counted. The simulation results of examples indicate the correctness and effectiveness of these methods, and also fully verify the function and influence of generator over-excitation limiter in full dynamic voltage stability research.

Entropy-driven phase regulation of high-entropy transition metal oxide and its enhanced high-temperature microwave absorption by in-situ dual phases

High-temperature microwave absorbers are significant for military equipment which experiences severe aerodynamic heat.In this work,high-entropy oxide(HEO)(FexCoNiCrMn)mOn with excellent high-temperature microwave absorption is studied.Driven by the effect of entropy,the composition of the oxide can be transformed from spinel-type phase(FexCoNiCrMn)_(3)O_(4) to corundum-type phase(FexCoNiCrMn)2O3 with the increasing content of iron.Only spinel-type or corundum-type structure composes the oxide when x≤3 or x≥5.But in-situ dual phases can coexist when x equals 4 during phase transition.Interestingly,obliged to abundant heterogeneous interfaces and crystal defects in the dual-phase HEO,magnetic property,dielectric polarization,and microwave loss ability are all well enhanced.The Smith chart analysis demonstrates the impedance matching condition is well improved due to the enhanced loss ability.These findings pave a new way for the adjustment of electromagnetic properties of HEO by entropy-driven phase regulation.Meanwhile,the dual-phase absorber can achieve better than 90%absorption in 9.6-12.4 GHz at 800℃ with a thickness of 2.6 mm,a low thermal diffusivity of 0.0038 cm^(2)/s at 900℃,and excellent high-temperature stability,which indicates it’s promising as a high-temperature microwave absorber.