Photochemical tuning of dynamic defects for high-performance atomically dispersed catalysts.

Developing active and stable atomically dispersed catalysts is challenging because of weak non-specific interactions between catalytically active metal atoms and supports. Here we demonstrate a general method for synthesizing atomically dispersed catalysts via photochemical defect tuning for controlling oxygen-vacancy dynamics, which can induce specific metal-support interactions. The developed synthesis method offers metal-dynamically stabilized atomic catalysts, and it can be applied to reducible metal oxides, including TiO2, ZnO and CeO2, containing various catalytically active transition metals, including Pt, Ir and Cu. The optimized Pt-DSA/TiO2 shows unprecedentedly high photocatalytic hydrogen evolution activity, producing 164 mmol g-1 h-1 with a turnover frequency of 1.27 s-1. Furthermore, it generates 42.2 mmol gsub-1 of hydrogen via a non-recyclable-plastic-photoreforming process, achieving a total conversion of 98%; this offers a promising solution for mitigating plastic waste and simultaneously producing valuable energy sources.

Inhibitory Activities of Dimeric Ellagitannins Isolated from Cornus alba on Benign Prostatic Hypertrophy.

Benign prostatic hypertrophy (BPH) is an intractable chronic inflammatory disease. We studied the efficacy of two ellagitannins, namely camptothin B (1) and cornusiin A (2) that were isolated from Cornus alba (CA) for the treatment of BPH, which is a common health issue in older men. The ellagitannins (1 and 2) were evaluated on its inhibitory activities of the enzyme 5α-reductase and tumor necrosis factor (TNF)-α, its interleukin (IL)-1ß, IL-6, and IL-8 production, and its anti-proliferation and apoptosis induction in prostate cells that show hypertrophy (RWPE-1 cell). In inhibition of 5α-reductase, the ellagitannins (1 and 2) showed potential effects, compared to the positive control, finasteride. In the case of IL-1ß, IL-6, IL-8, and TNF-α, 1 and 2 showed good inhibitory effects as compared to the control group treated with LPS. The ellagitannins (1 and 2) were also shown to inhibit proliferation of, and induce apoptosis in, the RWPE-1 cell. These results suggest that the ellagitannins (1 and 2) may be good candidates for the treatment of BPH.

Simulation of Capacitorless DRAM Based on the Polycrystalline Silicon Nanotube Structure with Multiple Grain Boundaries.

In this study, a capacitorless one-transistor dynamic random-access memory (1T-DRAM), based on polycrystalline silicon (poly-Si) nanotube structure with a grain boundary (GB), is designed and analyzed using technology computer-aided design (TCAD) simulation. In the proposed 1T-DRAM, the 1T-DRAM cell exhibited a sensing margin of 422 µA/µm and a retention time of 213 ms at T = 358 K with a single GB. To investigate the effect of random GBs, it was assumed that the number of GB is seven, and the memory characteristics depending on the location and number of GBs were analyzed. The memory performance rapidly degraded due to Shockley-Read-Hall recombination depending on the location and number of GBs. In the worst case, when the number of GB is 7, the mean of the sensing margin was 194 µA/µm, and the mean of the retention time was 50.4 ms. Compared to a single GB, the mean of the sensing margin and the retention time decreased by 59.7% and 77.4%, respectively.

Floatable photocatalytic hydrogel nanocomposites for large-scale solar hydrogen production.

Storing solar energy in chemical bonds aided by heterogeneous photocatalysis is desirable for sustainable energy conversion. Despite recent progress in designing highly active photocatalysts, inefficient solar energy and mass transfer, the instability of catalysts and reverse reactions impede their practical large-scale applications. Here we tackle these challenges by designing a floatable photocatalytic platform constructed from porous elastomer-hydrogel nanocomposites. The nanocomposites at the air-water interface feature efficient light delivery, facile supply of water and instantaneous gas separation. Consequently, a high hydrogen evolution rate of 163 mmol h-1 m-2 can be achieved using Pt/TiO2 cryoaerogel, even without forced convection. When fabricated in an area of 1 m2 and incorporated with economically feasible single-atom Cu/TiO2 photocatalysts, the nanocomposites produce 79.2 ml of hydrogen per day under natural sunlight. Furthermore, long-term stable hydrogen production in seawater and highly turbid water and photoreforming of polyethylene terephthalate demonstrate the potential of the nanocomposites as a commercially viable photocatalytic system.