Electrodeposition of CuAg alloy films from plating baths containing 3,5-diamino-1,2,4-triazole (DAT) as an inhibitor yields high surface area catalysts for the active and selective electroreduction ...of CO2 to multicarbon hydrocarbons and oxygenates. EXAFS shows the co-deposited alloy film to be homogeneously mixed. The alloy film containing 6% Ag exhibits the best CO2 electroreduction performance, with the Faradaic efficiency for C2H4 and C2H5OH production reaching nearly 60 and 25%, respectively, at a cathode potential of just −0.7 V vs RHE and a total current density of ∼ – 300 mA/cm2. Such high levels of selectivity at high activity and low applied potential are the highest reported to date. In situ Raman and electroanalysis studies suggest the origin of the high selectivity toward C2 products to be a combined effect of the enhanced stabilization of the Cu2O overlayer and the optimal availability of the CO intermediate due to the Ag incorporated in the alloy.
Electrodeposition of Ni or NiFe films exhibiting fractal-like behavior from plating baths containing an inhibitor, such as 3,5-diamino-1,2,4-triazole (DAT), is found to yield oxygen evolution ...reaction (OER) catalysts for alkaline solutions exhibiting high current densities (100 mA/cm2), high mass activity (∼1200 A/g of catalyst), high stability (>72 h), and low overpotentials (∼300 mV). By changing electrodeposition time, the activity of the catalyst can be tuned, with longer times yielding higher activities. The electrodeposition method works with any conductive substrate yielding unprecedented performance and providing an easy route to high activity catalysts.
Chemistry of Quantum Spin Liquids Chamorro, Juan R; McQueen, Tyrel M; Tran, Thao T
Chemical reviews,
03/2021, Letnik:
121, Številka:
5
Journal Article
Recenzirano
Odprti dostop
Quantum spin liquids are an exciting playground for exotic physical phenomena and emergent many-body quantum states. The realization and discovery of quantum spin liquid candidate materials and ...associated phenomena lie at the intersection of solid-state chemistry, condensed matter physics, and materials science and engineering. In this review, we provide the current status of the crystal chemistry, synthetic techniques, physical properties, and research methods in the field of quantum spin liquids. We highlight a number of specific quantum spin liquid candidate materials and their structure–property relationships, elucidating their fascinating behavior and connecting it to the intricacies of their structures. Furthermore, we share our thoughts on defects and their inevitable presence in materials, of which quantum spin liquids are no exception, which can complicate the interpretation of characterization of these materials, and urge the community to extend their attention to materials preparation and data analysis, cognizant of the impact of defects. This review was written with the intention of providing guidance on improving the materials design and growth of quantum spin liquids, and to paint a picture of the beauty of the underlying chemistry of this exciting class of materials.
Electrodeposition from plating baths containing 3,5-diamino-1,2,4-triazole (DAT) as an inhibitor gives Cu films exhibiting high surface area and high CO2 reduction activities. By changes in the pH ...and deposition current density, the morphologies of the Cu films are varied to exhibit wire, dot, and amorphous structures. Among these Cu films, the CuDAT-wire samples exhibit the best CO2 reduction activities activity with a Faradaic efficiency (FE) for C2H4 product formation reaching 40% at −0.5 V vs RHE, a FE for C2H5OH formation reaching 20% at −0.5 V vs RHE, and a mass activity for CO2 reduction at −0.7 V vs RHE of ∼700 A/g.
The rapid evolution of mobile technologies and the increasing diffusion of smartphones have given significant opportunities for innovative companies to create new payment solutions and offer ...value-added services to their customers. Near Field Communication (NFC) mobile payment has been emerging as a noticeable phenomenon that can enable consumers to turn their smartphones into digital wallets. Although there has been a lot of coverage on consumer acceptance of mobile payments, there are only few researches providing guideline to interpret NFC-based mobile payments adoption.
Taking into consideration of theoretical backgrounds of innovation diffusion and specific characteristics of NFC mobile payments, this study proposes a research framework to provide a profound understanding of factors facilitating or impeding the adoption of NFC-based mobile payments among Taiwanese consumers. The results revealed that intention to adopt NFC mobile payments is affected by most of product-related factors, personal-related factors and attractiveness of alternatives.
This paper is able to advance literature on innovation adoption and facilitate technology marketers in NFC mobile payments. It provides a useful guideline to help researchers investigate issues related to NFC mobile payments. It also brings some managerial implications by assisting relevant parties in NFC mobile payments ecosystem such as mobile network operators, card issuers, payment processing institutions, bank decision makers and merchants when devising their business strategies and marketing campaigns to facilitate NFC mobile payments.
•Theoretical backgrounds of innovation diffusion and specific characteristics of NFC mobile payments were considered.•Product-related factors had stronger impact on intention than personal-related factors.•PU was the most important driver, followed by compatibility and additional values of NFC mobile payments.•Perceived risk was the most important inhibitor, followed by attractiveness of alternatives.•The model explained 83% of the variance of intention to adopt NFC mobile payments.
A new deep-ultraviolet nonlinear optical material, RbMgCO3F, has been synthesized and characterized. The achiral nonpolar acentric material is second harmonic generation (SHG) active at both 1064 and ...532 nm, with efficiencies of 160 × α-SiO2 and 0.6 × β-BaB2O4, respectively, and exhibits a short UV cutoff, below 190 nm. RbMgCO3F possesses a three-dimensional structure of corner-shared Mg(CO3)2F2 polyhedra. Unlike other acentric carbonate fluorides, in this example, the inclusion of Mg2+ creates pentagonal channels where the Rb+ resides. Our electronic structure calculations reveal that the denticity of the carbonate linkage, monodentate or bidendate, to the divalent cation is a useful parameter for tuning the transparency window and achieving the sizable SHG response.
The coronavirus disease 2019 (COVID-19) pandemic causes fear, as its immediate consequences for the public have produced unprecedented challenges for the education and healthcare systems. We aimed to ...validate the fear of COVID-19 scale (FCoV-19S) and examine the association of its scores with health literacy and health-related behaviors among medical students. A cross-sectional study was conducted from 7 to 29 April 2020 on 5423 students at eight universities across Vietnam, including five universities in the North, one university in the Center, two universities in the South. An online survey questionnaire was used to collect data on participants' characteristics, health literacy, fear of COVID-19 using the FCoV-19S, and health-related behaviors. The results showed that seven items of the FCoV-19S strongly loaded on one component, explained 62.15% of the variance, with good item-scale convergent validity and high internal consistency (Cronbach's alpha = 0.90). Higher health literacy was associated with lower FCoV-19S scores (coefficient, B, -0.06; 95% confidence interval, 95%CI, -0.08, -0.04;
< 0.001). Older age or last academic years, being men, and being able to pay for medication were associated with lower FCoV-19S scores. Students with higher FCoV-19S scores more likely kept smoking (odds ratio, OR, 1.11; 95% CI, 1.08, 1.14;
< 0.001) or drinking alcohol (OR, 1.04; 95% CI, 1.02, 1.06;
< 0.001) at an unchanged or higher level during the pandemic, as compared to students with lower FCoV-19S scores. In conclusion, the FCoV-19S is valid and reliable in screening for fear of COVID-19. Health literacy was found to protect medical students from fear. Smoking and drinking appeared to have a negative impact on fear of COVID-19. Strategic public health approaches are required to reduce fear and promote healthy lifestyles during the pandemic.
Noncentrosymmetric mixed-metal carbonate fluorides are promising materials for deep-ultraviolet (DUV) nonlinear optical (NLO) applications. We report on the synthesis, characterization, ...structure–property relationships, and electronic structure calculations on two new DUV NLO materials: KMgCO3F and Cs9Mg6(CO3)8F5. Both materials are noncentrosymmetric (NCS). KMgCO3F crystallizes in the achiral and nonpolar NCS space group P6̅2m, whereas Cs9Mg6(CO3)8F5 is found in the polar space group Pmn21. The compounds have three-dimensional structures built up from corner-shared magnesium oxyfluoride and magnesium oxide octahedra. KMgCO3F (Cs9Mg6(CO3)8F5) exhibits second-order harmonic generation (SHG) at both 1064 and 532 nm incident radiation with efficiencies of 120 (20) × α-SiO2 and 0.33 (0.10) × β-BaB2O4, respectively. In addition, short absorption edges of <200 and 208 nm for KMgCO3F and Cs9Mg6(CO3)8F5, respectively, are observed. We compute the electron localization function and density of states of these two compounds using first-principles density functional theory, and show that the different NLO responses arise from differences in the denticity and alignment of the anionic carbonate units. Finally, an examination of the known SHG active AMCO3F (A = alkali metal, M = alkaline earth metal, Zn, Cd, or Pb) materials indicates that, on average, smaller A cations and larger M cations result in increased SHG efficiencies.
The COVID-19 pandemic has been influencing people's psychological health, especially in pregnant women. We aimed to examine associated factors of fear of COVID-19, anxiety and depression among ...pregnant women during the pandemic where the impacts of healthy eating behaviour (HES) and health literacy (HL) were emphasized.
A cross-sectional study was conducted between 14 February 2020 and 31 May 2020 in 18 health centres and hospitals across Vietnam. Data of 518 pregnant women were analysed, including socio-demographics, pregnant-related factors, HES, HL, health-related behaviours, fear of COVID-19 scale (FCoV-19S), anxiety (using the generalized anxiety disorder (GAD-7)) and depression (using the patient health questionnaire with 9 items (PHQ-9)). Regression analysis was utilized to explore the associations.
Pregnant women with higher scores of HES and HL had lower likelihood of anxiety (odds ratio, OR, 0.79; 95% confidence interval (95%CI), 0.73, 0.87; p < .001; and OR, 0.94; 95%CI, 0.90, 0.99; p = .018) and depression (OR, 0.84; 95%CI, 0.78, 0.91; p < .001; and OR, 0.96; 95%CI, 0.91, 0.99; p = .044), respectively. Pregnant women being employed had a lower FCoV-19S score (regression coefficient, B, −1.46; 95%CI, −2.51, −0.40; p = .007). Besides, other significant predictors of anxiety were eating healthier during the pandemic, unchanged or more physical activity, elevated gestational age and smoking. Other significant predictors of depression were eating healthier during the pandemic, elevated gestational age and smoking.
Among others, HES and HL had positive impacts on protecting pregnant women against anxiety and depression. Improving HES and HL should be addressed as a strategic approach to improve reproductive health during the pandemic.
KEY MESSAGE
The COVID-19 pandemic influences antenatal mental disorders with the higher level as opposed to that before the pandemic.
Healthy eating behaviour and better health literacy (HL) had critical roles in lowering prenatal anxiety and depression during the COVID-19 crisis.
Strategic approaches for improving healthy eating and HL should be recommended for protecting pregnant women from mental health problems during the pandemic.
Noncentrosymmetric (NCS) materials feature an exciting array of functionalities such as nonlinear optical (NLO) responses and topological spin textures (skyrmions). While NLO materials and magnetic ...skyrmions display two different sets of physical properties, their design strategies are deeply connected in terms of atomic-scale precision, structural customization, and electronic tunability. Despite impressive progress in studying these systems separately, a joint road map for navigating the chemical principles for NCS materials remains elusive. This review unites two subtopics of NCS systems, NLO materials and magnetic skyrmions, offering a multifaceted narrative of how to translate the often-abstract fundamentals to the targeted functionalities while inviting innovative approaches from the community. We outline the design principles central to the desired properties by exemplifying relevant examples in the field. We supplement materials chemistry with pertinent electronic structures to demonstrate the power of the fundamentals to create systems integration relevant to foreseeable societal impacts in frequency-doubling instrumentation and spin-based electronics.
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