Solution-Processed PEDOT:PSS/Graphene Composites as the Electrocatalyst for Oxygen Reduction Reaction

Composites of poly­(3,4-ethylenedioxythiophene):poly­(styrenesulfonate) (PEDOT:PSS) and reduced graphene oxide (rGO) have been prepared by solution mixing and applied as electrocatalysts for oxygen reduction reaction (ORR) after treatment with concentrated H₂SO₄. The blending of rGO induces the conformational change of PEDOT chains from benzoid to quionoid structure and charge transfer from rGO to PEDOT. H₂SO₄ post-treatment can remove part of insulating PSS from the surface of the PEDOT:PSS/rGO composite film, resulting in a significant conductivity enhancement of the composite. This synergistic effect makes the H₂SO₄-treated PEDOT:PSS/rGO composite a promising catalyst for ORR. It exhibits enhanced electrocatalytic activity, better tolerance to a methanol crossover effect and CO poisoning, and longer durability than those of the platinum/carbon catalyst

Trace Level Co–N Doped Graphite Foams as High-Performance Self-Standing Electrocatalytic Electrodes for Hydrogen and Oxygen Evolution

The development of eco-friendly electrocatalysts with high performance and low cost for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is significant for renewable energy storage. Here, trace level (0.11–0.18 wt %) Co–N doped graphite foam (Co–N/GF) was reported to work as a bifunctional high-performance and self-standing electrode for both HER and OER in alkaline electrolyte. The catalytic activities of Co–N/GFs with different annealing temperatures (600, 700, 800, 900, and 1000 °C) were carefully studied. Among them, Co–N/GF-900 exhibited the best HER activity and Co–N/GF-700 showed the best OER activity, achieving the current density of 10 mA cm^–2 at low overpotentials of 165 and 313 mV, respectively. In addition, both of these electrodes exhibited long-term durability. Co–N/GF electrodes were further constructed as a catalytic cathode and anode couple (Co–N/GF-900∥Co–N/GF-700) for overall water splitting, exhibiting a low cell voltage of 1.68 V and good long-term stability. Our work reveals that introducing a trace level of Co–N into graphite foam can significantly enhance its electrocatalytic activity and stability for both HER and OER

Gas Separation through Bilayer Silica, the Thinnest Possible Silica Membrane

Membrane-based gas separation processes can address key challenges in energy and environment, but for many applications the permeance and selectivity of bulk membranes is insufficient for economical use. Theory and experiment indicate that permeance and selectivity can be increased by using two-dimensional materials with subnanometer pores as membranes. Motivated by experiments showing selective permeation of H₂/CO mixtures through amorphous silica bilayers, here we perform a theoretical study of gas separation through silica bilayers. Using density functional theory calculations, we obtain geometries of crystalline free-standing silica bilayers (comprised of six-membered rings), as well as the seven-, eight-, and nine-membered rings that are observed in glassy silica bilayers, which arise due to Stone–Wales defects and vacancies. We then compute the potential energy barriers for gas passage through these various pore types for He, Ne, Ar, Kr, H₂, N₂, CO, and CO₂ gases, and use the data to assess their capability for selective gas separation. Our calculations indicate that crystalline bilayer silica, which is less than a nanometer thick, can be a high-selectivity and high-permeance membrane material for ³He/⁴He, He/natural gas, and H₂/CO separations

Additional file 3: Figure S3. of Long non-coding RNA CASC2 suppresses epithelial-mesenchymal transition of hepatocellular carcinoma cells through CASC2/miR-367/FBXW7 axis

miR-367 reversed the anti-metastatic effects of CASC2 on HCC cells. (A) FBXW7 level was reversed by miR-367 in CASC2-overexpressing MHCC-97H cells. (B) miR-367 expression was rescued by miR-367 mimics in CASC2-overexpressing MHCC-97H cells. (C) miR-367 abolished the inhibitory effects of CASC2 on migration and invasion of MHCC-97H cells. (D) miR-367 abrogated the inhibitory effects of CASC2 on EMT progression of MHCC-97H cells. *P < 0.05, **P < 0.01, ***P < 0.001. (TIFF 1008 kb

Additional file 4: Figure S4. of Long non-coding RNA CASC2 suppresses epithelial-mesenchymal transition of hepatocellular carcinoma cells through CASC2/miR-367/FBXW7 axis

FBXW7 rescued the pro-metastatic effects of miR-367 on HCC cells. (A) FBXW7 overexpression increased the expression of E-cadherin and decreased the expression of Vimentin in Hep-3B cells. (B) FBXW7 abolished the promoting effects of miR-367 on EMT progression of Hep-3B cells. (C) FBXW7 abrogated the pro-metastatic effects of miR-367 on migration and invasion of Hep-3B cells. **P < 0.01. (TIFF 878 kb

Size Fractionation of Graphene Oxide Nanosheets via Controlled Directional Freezing

The properties and functions of graphene oxide (GO)-based materials strongly depend on the lateral size and size distribution of GO nanosheets; therefore, GO and its derivatives with narrow size distributions are highly desired. Here we report the size fractionation of GO nanosheets by controlled directional freezing of GO aqueous dispersions. GO nanosheets with a narrow size distribution can be obtained by controlling the growth rate of the freezing front. This interesting phenomenon can be explained by the adsorption of GO nanosheets on the ice crystal surface in combination with the stratification of GO nanosheets at the ice growth front. Such a convenient size fractionation approach will be essential for practical applications of chemically modified graphene, including GO, reduced GO, and their assemblies or composites