Band Alignment, Built-In Potential, and the Absence of Conductivity at the LaCrO3/SrTiO3(001) Heterojunction

Core-level and valence-band x-ray photoemission spectra measured for molecular-beam-epitaxy-grown LaCrO3/SrTiO3(001) yield band offsets and potential gradients within the LaCrO3 sufficient to trigger an electronic reconstruction to alleviate the polarity mismatch. Yet, the interface is insulating. Based on first principles calculations, we attribute this unexpected result to interfacial cation mixing combined with charge redistribution within CrO2 layers, enabled by low-lying d states within LaCrO3, which suppresses an electronic reconstruction

Carbon Dioxide-Assisted Fabrication of Highly Uniform Submicron-sized Colloidal Carbon Spheres via Hydrothermal Carbonization Using Soft Drink

An eco-friendly and economical method for the formation of highly uniform-sized carbon spheres by hydrothermal dehydration/condensation of a commercial carbonated beverage at 200 A degrees C is reported. Until now, the effect of an extra pressure which is built up by dissolved CO2 on the generation of carbon spheres under hydrothermal condition less than 250 A degrees C hasn't been demonstrated yet. In general, a complicated reactor is required to put overpressure on the autoclave vessel by adding inert gases, whereas the manipulation of a carbonated beverage including fructose and glucose molecules as precursors is favorable to design a simple experimental set-up and to investigate the effect of extra pressure on the growth of carbon spheres under mild hydrothermal condition. Herein, CO2 dissolved in the beverage accelerates the dehydration kinetics of the dissolved sugar molecules leading to production of homogeneous carbon spheres having a diameter less than 850 nm. In addition, the rough surface of these carbon spheres likely results from continuous Ostwald ripening of constituent microscopic carbon-containing spheres that are formed by subsequent polymerization of intermediate hydroxymethylfurfural molecules.X118sciescopu

Catalytic templating approaches for three-dimensional hollow carbon/graphene oxide nano-architectures

We report a catalytic templating method to synthesize well-controlled three-dimensional carbon nano-architectures. Depending on graphene oxide content, the morphology can be systematically tuned from layered composites to 3D hollow structures to microporous materials. The composites with high surface area and high porosity induce a significant enhancement to its capacitance at high current density.open112022sciescopu

Airborne soil organic particles generated by precipitation

Airborne organic particles play a critical role in Earth's climate, public health, air quality, and hydrological and carbon cycles. However, sources and formation mechanisms for semi-solid and solid organic particles are poorly understood and typically neglected in atmospheric models. Laboratory evidence suggests that fine particles can be formed from impaction of mineral surfaces by droplets. Here, we use chemical imaging of particles collected following rain events in the Southern Great Plains, Oklahoma, USA and after experimental irrigation to show that raindrop impaction of soils generates solid organic particles. We find that after rain events, sub-micrometre solid particles, with a chemical composition consistent with soil organic matter, contributed up to 60% of atmospheric particles. Our irrigation experiments indicate that intensive water impaction is sufficient to cause ejection of airborne soil organic particles from the soil surface. Chemical imaging and micro-spectroscopy analysis of particle physico-chemical properties suggest that these particles may have important impacts on cloud formation and efficiently absorb solar radiation. We suggest that raindrop-induced formation of solid organic particles from soils may be a widespread phenomenon in ecosystems such as agricultural systems and grasslands where soils are exposed to strong, episodic precipitation events

Airborne soil organic particles generated by precipitation

Airborne organic particles play a critical role in Earth's climate, public health, air quality, and hydrological and carbon cycles. However, sources and formation mechanisms for semi-solid and solid organic particles are poorly understood and typically neglected in atmospheric models. Laboratory evidence suggests that fine particles can be formed from impaction of mineral surfaces by droplets. Here, we use chemical imaging of particles collected following rain events in the Southern Great Plains, Oklahoma, USA and after experimental irrigation to show that raindrop impaction of soils generates solid organic particles. We find that after rain events, sub-micrometre solid particles, with a chemical composition consistent with soil organic matter, contributed up to 60% of atmospheric particles. Our irrigation experiments indicate that intensive water impaction is sufficient to cause ejection of airborne soil organic particles from the soil surface. Chemical imaging and micro-spectroscopy analysis of particle physico-chemical properties suggest that these particles may have important impacts on cloud formation and efficiently absorb solar radiation. We suggest that raindrop-induced formation of solid organic particles from soils may be a widespread phenomenon in ecosystems such as agricultural systems and grasslands where soils are exposed to strong, episodic precipitation events