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The cordierite‐based ceramic catalyst filter (CCF) has attracted considerable attention as a promising future air purification system due to its ability to filtrate particulate matter (PM), as well as decompose volatile organic compounds (VOCs) through ultraviolet (UV)‐activated photocatalytic reactions. Its performance, however, is strictly limited because majority of UV photons are absorbed near the entrance of the high‐aspect‐ratio air‐flow channels, thus, only a limited portion of photocatalysts is activated during the flow of polluted air. In this study, a high‐performance CCF is presented featuring textured waveguides (TWs) aligned with an array of UV light‐emitting diodes (LEDs) emitting at a peak wavelength of 365 nm, which are inserted into an array of high‐aspect‐ratio channels. TWs ensure the delivery of UV photons deep inside channels via total internal reflection and scattering, enabling the activation of majority of photocatalysts, resulting in remarkable improvement in VOCs removal efficiency. The proposed CCF system exhibits much higher formaldehyde (HCHO) removal efficiency by 70% compared to conventional CCF systems even subjected to much lower UV light power densities. It is strongly believed that it is possible to further improve the removal efficiency, while maintaining effective PM filtering and ultralow electrical power consumption, by optimization of the geometry of the CCF system with TWs. [ABSTRACT FROM AUTHOR]

Electrochemical reduction of CO2 to chemical fuels with a transition metal-based single atom catalyst (SAC) offers a promising strategy to reduce CO2 with high catalytic selectivity. To date, the study of atomically dispersed SACs has been mainly conducted by using a conventional H-type cell system with limited solubility of CO2 in aqueous electrolytes, resulting in large overpotentials and low current density. Here, we reported a pyrrolic N-stabilized Ni SAC with low-coordinated Ni–Nx sites by thermal activation of Ni ZIF-8, which was tested in a 3-compartment microfluidic flow cell system at the industrial level. When the pyrolysis temperature increased from 800 °C (Ni SAC-800) to 1000 °C (Ni SAC-1000), the content ratio of pyrrolic N/pyridinic N increased from 0.37 to 1.01 as well as the coordination number of Ni in Ni–Nx sites decreased from 3.14 to 2.63. Theoretical calculations revealed that the synergistic effect between the high content ratio of pyrrolic N and low-coordinated Ni can decrease the energy barrier for the desorption of *CO during the CO2RR. Therefore, Ni SAC-1000 exhibited superior catalytic performances with high CO selectivity (FECO = 98.24% at −0.8 VRHE) compared to that of Ni SAC-800 (FECO = 40.76% at −0.8 VRHE). Moreover, Ni SAC-1000 based on the flow cell system showed a higher current density (∼200 mA cm−2) compared to that of the H-type cell system (∼20 mA cm−2). As a result, this study experimentally demonstrated that the pyrrolic N-stabilized and low-coordinated Ni SAC-1000 in the microfluidic flow cell reactor provides great chances for scaling up the productivity of the CO2RR at the industrial level. [ABSTRACT FROM AUTHOR]

Here we introduce bismuth‐based catalysts for the efficient electrochemical reduction of CO2 to formic acid (HCOOH), which are composed of petal‐shaped Bi2O2CO3 (BOC) that spontaneously formed from Bi thin film in aqueous carbonate solution at room temperature. During the electrochemical reduction process, the BOC petals transform to reduced BOC (R‐BOC) consisting of individual BOC and Bi domains. Lattice mismatch between both domains induces biaxial strain at the interfaces. Density functional theory calculations suggest that the tensile strain on the Bi domain stabilizes the *OCHO intermediate, reducing the thermodynamic barrier toward CO2 conversion to HCOOH. Together with the thermodynamic benefit and the unique nanoporous petal‐shaped morphology, R‐BOC petals have a superior Faradaic efficiency of 95.9% at −0.8 VRHE for the electrochemical conversion of CO2 to HCOOH. This work demonstrates that the spontaneously formed binary phases with desirable lattice strain can increase the activity of bismuth catalysts to the CO2 reduction reaction; such a strategy can be applicable in design of various electrocatalysts. [ABSTRACT FROM AUTHOR]

We investigated the relationship between grain boundary (GB) oxidation of Cu-Ag thin-film catalysts and selectivity of the (photo)electrochemical CO 2 reduction reaction (CO 2 RR). The change in the thickness of the Cu thin film accompanies the variation of GB density, and the Ag layer (3 nm) has an island-like morphology on the Cu thin film. Therefore, oxygen from ambient air penetrates into the Cu thin film through the GB of Cu and binds with it because the uncoordinated Cu atoms at the GBs are unstable. It was found that the Cu thin film with a small grain size was susceptible to spontaneous oxidation and degraded the faradaic efficiency (FE) of CO and CH 4 . However, a relatively thick (≥80 nm) Cu layer was effective in preventing the GB oxidation and realized catalytic properties similar to those of bulk Cu-Ag catalysts. The optimized Cu (100 nm)-Ag (3 nm) thin film exhibited a unique bifunctional characteristic, which enables selective production of both CO (FE CO = 79.8%) and CH 4 (FE CH4 = 59.3%) at a reductive potential of -1.0 and -1.4 V RHE , respectively. Moreover, the Cu-Ag thin film was used as a cocatalyst for photo-electrochemical CO 2 reduction by patterning the Cu-Ag thin film and a SiO 2 passivation layer on a p-type Si photocathode. This novel architecture improved the selectivity of CO and CH 4 under light illumination (100 mW/cm 2 ).

Background/aims: The eradication rate of Helicobacter pylori ( H. pylori ) has been decreasing recently in Korea due to antibiotics resistance. The aim of this study was to investigate the trend of eradication rate and clinical factors affecting the eradication rate of H. pylori in the last 10 years in west Gyeonggi-do, Korea., Methods: The trends of eradication rate of H. pylori , gender, age, concomitant mediations, and clinical factors were retrospectively evaluated in patients with H. pylori infection between 2006 and 2015 (n=2,485)., Results: The overall H. pylori eradication rate for the standard triple therapy was 82.5%. The annual eradication rates from 2006 to 2015 were 90%, 77.9%, 75.8%, 83.2%, 85.6%, 90.1%, 81.3%, 81.1%, 78.7%, and 78.8%, respectively, showing a significant decrement during the last five years (p<0.001). Higher eradication rate was observed in males than in females (p<0.001). Esomeprazole showed a higher eradication rate compared with pantoprazole between 2006 and 2010 (p<0.022). Age and the use of probiotics and mucosal protective agents played no significant role in the H. pylori eradication rate. The overall eradication rate for bismuth-based quadruple therapy was 94.4%., Conclusions: The eradication rate of H. pylori over the last 10 years for first-line therapy ranged from 75.8 to 90.1%; the eradication rate for triple therapy has declined. However, the eradication rate for quadruple therapy has remained unchanged over the last 10 years.