Magnetic field assisted α-Fe2O3/Zn1-xFexO heterojunctions for accelerating antiviral agents degradation under visible-light.

Reducing the recombination efficiency of photo-induced carriers has been found as an effective means to improve the degradation of antiviral agents. Given that the Lorentz forces can cause the abnormal charge to move in the opposite direction, external magnetic field improved α-Fe2O3/Zn1-xFexO heterojunctions (FZHx) were developed to remove increasing antiviral agents that were attributed to the COVID-19 pandemic under visible light. The characterization of the mentioned FZHx in the external magnetic field indicated that FZHx had perfect photocatalytic activity for degrading antiviral agents. In the external magnetic field, the quantities of photo-generated carriers and free radicals (•OH and •O2 -) derived from FZHx increased significantly, which improved antiviral agent removal by 30.0%. Though the band structure (α-Fe2O3) is unlikely to change due to some orders of magnitude weaker of Zeeman energy in magnetic fields, which insignificantly impacts photocatalytic performance. However, this study proposed a strategy of negative magnetoresistance effects and heterojunctions to facilitate the separation and transfer of photo-induced carriers in magnetic fields. Based on the proposed strategy, spin oriented electrons were selected and accumulated on the conduction band, which contributed to the degradation of antiviral agents. Overall, this study presented novel insights into the improved degradation performance of antiviral agents by applying Fe-based heterojunctions in an external magnetic field.

Rodlike Cadmium-Incorporated Zinc Tungstate Nanoarchitecture Fabricated by a Facile and Template-Free Strategy as a Photocatalyst for the Effective Degradation of Organic Pollutants in Sewage.

Fabricating nanostructures and doping engineering are beneficial to tailor the photocatalytic activity of semiconductor materials, and the semiconducting photocatalysis is deemed to be one of the potential protocols to handle the environmental pollution and energy crisis issues. Herein, rodlike Cd-doped ZnWO4 Zn1-x Cd x WO4 nanoarchitectures were triumphantly prepared by a template-free strategy. The crystal structure, chemical state, optical, and photocatalytic features of the Zn1-x Cd x WO4 nanoarchitectures were studied using a variety of characterizations. The Zn1-x Cd x WO4 nanoarchitectures exhibit glorious photocatalytic performance compared with pristine ZnWO4 for the degradation of methyl orange in sewage. Mechanistic studies were executed for getting insights into the photocatalytic degradation process, and the remarkable photocatalytic property of the doped ZnWO4 nanoarchitectures is attributed to the boosted optical absorptive efficiency and the valid segregation and transmission of photogenerated charge carriers deriving from doping effects. The doped nanoarchitectures of this work have promising applications in the territories such as environment and energy chemistry, and the insight proposed in this work will contribute to develop other functionalized nanoarchitectures.

Aggregation of Silica Nanoparticles in Sol-Gel Processes to Create Optical Coatings with Controllable Ultralow Refractive Indices.

Optical coatings with controllable ultralow refractive indices are of profound significance in optical areas. However, it remains a challenge to fabricate such coatings using a simple method. Here we develop an effective and simple approach to create ultra-low-index coatings. This approach was based on a modified sol-gel process, with a key process that involved the aggregation of silica nanoparticles via the addition of a polymer surfactant (e.g., polyvinylpyrrolydone) in sols before coating. The approach involves three steps: the synthesis of silica sols under ammonia catalysis in ethanol (Stöber method), the addition of polyvinylpyrrolydone in the silica sols to induce the aggregation of the silica nanoparticles, and the formation of ultra-low-index coatings by depositing the aggregated silica sols on substrates. Through varying the aggregation extent, this approach produced coatings with controllable refractive indices ranging from 1.17 to 1.07. To the best of our knowledge, the minimum index value of 1.07 from our coating is among the lowest refractive indices ever reported. The ultra-low-index coatings demonstrated excellent optical properties, with which perfect quarter-wavelength antireflection coatings (maximum transmittance ∼100%) and broadband antireflection coatings (transmittance >98% from 400 to 1100 nm) can be prepared. One advantage of the antireflection coatings is that their transmission is less dependent on the refractive index and the thickness of the stacking layer, which make it promising in large-scale production. Moreover, the coatings can be made hydrophobic (water contact angle 136°) by exposing the coatings to a hexamethyldisilazane atmosphere, exhibiting high environmental stability in a humid environment. The aggregation of silica nanoparticles in sol-gel processes provides a scalable alternative to the current approaches for creating ultra-low-index coatings.

Ni Hierarchical Structures Supported on Titania Nanowire Arrays as Efficient Nonenzymatic Glucose Sensor.

Developing new advanced nonenzymatic electrochemical nano-sensors for glucose detection has attracted intensive attraction. In this work, we designed a novel nanocomposite nonenzymatic glucose sensor by fabricating hierarchically nanostructured metal nickel on titania nanowire arrays, which was loaded on a transparent conductive substrate (i.e., fluorine-doped tin oxide, FTO) surface by mild hydrothermal method. Due to the large surface area of the hierarchically nanostructured Ni and fast electron transfer of the TiO2 nanowire arrays electrode, the nanocomposite electrode shows excellent electrochemical activity toward the oxidation of glucose. The electrode exhibits high sensitivity in detecting glucose concentration (1472 µA mM-1 cm-2) with a wide linear range from 2×10-4 M to 2×10-3 M, fast response time (within 5 s), and small detection limit (10 µM) (S/N = 3). The good analytical performance, low cost and simple preparation method make this novel electrode material promising for the development of effective glucose nonenzymatic glucose sensor.

Controlled Self-Assembled NiFe Layered Double Hydroxides/Reduced Graphene Oxide Nanohybrids Based on the Solid-Phase Exfoliation Strategy as an Excellent Electrocatalyst for the Oxygen Evolution Reaction.

Layered double hydroxides (LDHs), as an effective oxygen evolution reaction (OER) electrocatalyst, face many challenges in practical applications. The main obstacle is that bulk materials limit the exposure of active sites. At the same time, the poor conductivity of LDHs is also an important factor. Exfoliation is one of the most direct and effective strategies to increase the electrocatalytic properties of LDHs, leading to exposure of many active sites. However, developing an efficient exfoliation strategy to exfoliate LDHs into stable monolayer nanosheets is still challenging. Therefore, we report a new and efficient solid-phase exfoliation strategy to exfoliate NiFe LDH and graphene oxide (GO) into monolayer nanosheets and the exfoliating ratios of NiFe LDH and GO can reach up to 10 and 5 wt %, respectively. Based on the solid-phase exfoliation strategy, we accidentally discovered that there is a dynamic evolution process between NiFe-LDH nanosheets (NiFe-LDH-NS) and GO nanosheets (GO-NS) to assemble new NiFe-LDH/GO nanohybrids, i.e., NiFe-LDH-NS could be horizontal bespreading on GO-NS or well-organized standing on GO-NS, or both simultaneously. The electrocatalytic OER property test results show that NiFe-LDH/RGO-3 (NFRG-3) nanohybrids obtained by the reduction treatment of NiFe-LDH/GO-3 (NFGO-3) nanohybrids, in which NiFe-LDH-NS are well-organized standing on GO-NS, have excellent electrocatalytic properties for OER in an alkaline solution (with a small overpotential of 273 mV and a Tafel slope of 49 mV dec-1 at the current density of 30 mA cm-2). The excellent electrocatalytic properties for OER of NFRG-3 nanohybrids could be attributed to the unique three-dimensional arraylike structure with many active sites. At the same time, reduced graphene oxide (RGO) with excellent conductivity can improve the charge-transfer efficiency and synergistically improve OER properties of nanohybrids.

Orientation-dependent structural and photocatalytic properties of LaCoO3 epitaxial nano-thin films.

LaCoO3 epitaxial films were grown on (100), (110) and (111) oriented LaAlO3 substrates by the polymer-assisted deposition method. Crystal structure measurement and cross-section observation indicate that all the LaCoO3 films are epitaxially grown in accordance with the orientation of LaAlO3 substrates, with biaxial compressive strain in the ab plane. Owing to the different strain directions of CoO6 octahedron, the mean Co-O bond length increases by different amounts in (100), (110) and (111) oriented films compared with that of bulk LaCoO3, and the (100) oriented LaCoO3 has the largest increase. Photocatalytic degradation of methyl orange indicates that the order of photocatalytic activity of the three oriented films is (100) > (111) > (110). Combined with analysis of electronic nature and band structure for LaCoO3 films, it is found that the change of the photocatalytic activity is closely related to the crystal field splitting energy of Co3+ and Co-O binding energy. The increase in the mean Co-O bond length will decrease the crystal field splitting energy of Co3+ and Co-O binding energy and further reduce the value of band gap energy, thus improving the photocatalytic activity. This may also provide a clue for expanding the visible-light-induced photocatalytic application of LaCoO3.

Patient-physician mistrust and violence against physicians in Guangdong Province, China: a qualitative study.

OBJECTIVE: To better understand the origins, manifestations and current policy responses to patient-physician mistrust in China. DESIGN: Qualitative study using in-depth interviews focused on personal experiences of patient-physician mistrust and trust. SETTING: Guangdong Province, China. PARTICIPANTS: One hundred and sixty patients, patient family members, physicians, nurses and hospital administrators at seven hospitals varying in type, geography and stages of achieving goals of health reform. These interviews included purposive selection of individuals who had experienced both trustful and mistrustful patient-physician relationships. RESULTS: One of the most prominent forces driving patient-physician mistrust was a patient perception of injustice within the medical sphere, related to profit mongering, knowledge imbalances and physician conflicts of interest. Individual physicians, departments and hospitals were explicitly incentivised to generate revenue without evaluation of caregiving. Physicians did not receive training in negotiating medical disputes or humanistic principles that underpin caregiving. Patient-physician mistrust precipitated medical disputes leading to the following outcomes: non-resolution with patient resentment towards physicians; violent resolution such as physical and verbal attacks against physicians; and non-violent resolution such as hospital-mediated dispute resolution. Policy responses to violence included increased hospital security forces, which inadvertently fuelled mistrust. Instead of encouraging communication that facilitated resolution, medical disputes sometimes ignited a vicious cycle leading to mob violence. However, patient-physician interactions at one hospital that has implemented a primary care model embodying health reform goals showed improved patient-physician trust. CONCLUSIONS: The blind pursuit of financial profits at a systems level has eroded patient-physician trust in China. Restructuring incentives, reforming medical education and promoting caregiving are pathways towards restoring trust. Assessing and valuing the quality of caregiving is essential for transitioning away from entrenched profit-focused models. Moral, in addition to regulatory and legal, responses are urgently needed to restore trust.