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To improve the gas-sensing performance of metal-oxide-semiconductors, the effect of defects on gas-sensing properties has been widely investigated. Nevertheless, although the metal cation defect is the dominative acceptor defect in p-type semiconductors, its effect on the gas-sensing properties remains blank, which leads to a hindrance for further developing p-type semiconductor-based gas sensors. Accordingly, to eleborate the effect of metal cation defects on the sensing properties, mesoporous NiO nanosheets with different amounts of nickel vacancies were prepared by annealing at different temperatures. It was found that the amount of nickel vacancies increased with increasing the annealing temperature. Gas-sensing studies revealed that the NiO with a higher concentration of nickel vacancies exhibited higher sensitivity to NO2 at room temperature. With further increasing the annealing temperature to 600 °C, although the rapid decrease in the specific surface area of the NiO might limit the physisorption of NO2, the NiO could also present a better sensitivity to NO2 due to the abundant nickel vacancies with high activity. Furthermore, an in situ DRIFTS study demonstrated that the number of adsorbed nitrate and nitrite species on NiO surfaces increased with increasing the amount of nickel vacancies, indicating that the nickel vacancies acted as the dominative active sites participating in the gas–solid reaction and then determined the room-temperature sensing properties. According to the defect ionization equation, a hole conduction model was further proposed to decipher the dependency of sensing properties on the metal cation defects. We hope this work could make us better understand the roles of cation defect in the sensing properties, and it could also benefit the improvement of p-type semiconductor-based gas sensors.

Developing a facile and cost-efficient method to synthesize carbon-based nanomaterials possessing excellent structural and functional properties has become one of the most attractive topics in energy conversion and storage fields. In this study, density functional theory calculation results reveal the origin of high oxygen reduction reaction (ORR) activity predominantly derived from the synergistic effect of intrinsic defects and heteroatom dopants (e.g., N, S) that modulate the bandgap and charge density distribution of carbon matrix. Under the guidance of the first-principle prediction, by using ultralight biomass waste as precursor of C, N, and S elements, a defect-rich and N/S dual-doped cheese-like porous carbon nanomaterial is successfully designed and constructed. Herein, the intrinsic defects are artfully generated in terms of alkaline and ammonia activation. The electrochemical measurements display that such a material owns a comparable ORR activity (E = 0.835 V) to the commercial Pt/C catalyst, along with splendid durability and methanol tolerance in alkali media. Furthermore, as cathode catalyst, it displays a high Zn-air battery performance. The excellent ORR activity of the catalyst can be attributed to its unique 3D porous architecture, abundant intrinsic defects, and high-content active heteroatom dopants in the carbon matrix.

These results demonstrate that aPKC-ι promotes EMT and induces immunosuppression through the aPKC-ι/P-Sp1/Snail signaling pathway and may be a potential therapeutic target for CCA. (Hepatology 2017;66:1165-1182).

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Iron corrosion causes a great damage to the economy due to the function attenuation of iron‐based devices. However, the corrosion products can be used as active materials for some electrocatalytic reactions, such as oxygen evolution reaction (OER). Herein, the oxygen corrosion on Fe foams (FF) to synthesize effective self‐supporting electrocatalysts for OER, leading to “turning waste into treasure,” is regulated. A dual chloride aqueous system of “NaCl‐NiCl2” is employed to tailor the structures and OER properties of corrosion layers. The corrosion behaviors identify that Cl− anions serve as accelerators for oxygen corrosion, while Ni2+ cations guarantee the uniform growth of corrosion layers owing to the appeared chemical plating. The synergistic effect of “NaCl‐NiCl2” generates one of the highest OER activities that only an overpotential of 212 mV is required to achieve 100 mA cm−2 in 1.0 m KOH solution. The as‐prepared catalyst also exhibits excellent durability over 168 h (one week) at 100 mA cm−2 and promising application for overall water splitting. Specially, a large self‐supporting electrode (9 × 10 cm2) is successfully synthesized via this cost‐effective and easily scale‐up approach. By combining with corrosion science, this work provides a significant stepping stone in exploring high‐performance OER electrocatalysts.

It is of paramount importance to explore high efficient and stable electrocatalysts toward anodic hydrogen oxidation reaction (HOR) in anion exchange membrane fuel cells. Herein, a new class of ternary (Pt 0.9 Pd 0.1 ) 3 Fe intermetallic is developed with excellent performance toward alkaline HOR. Specifically, the Pd-substitution facilitates the formation of L1 2 -Pt 3 Fe intermetallic at a lower annealing temperature. Electrochemical analysis and density functional theory calculations indicate that the in-situ formed interstitial alloying PdH x during the electrochemical cycle widens the d-band structure of (Pt 0.9 Pd 0.1 ) 3 Fe and shifts downward the d-band center toward the Fermi level. The optimized ligand effect from PdH x gives rise to the encouraging activity for alkaline HOR. Meanwhile, a stepby-step monitoring technique and ex situ CO-stripping voltammetry jointly demonstrate that ordered atoms' arrangement of (Pt 0.9 Pd 0.1 ) 3 Fe intermetallic contributes to stabilize the local coordination environment and enables the maintenance of the ligand effect from the in situ formed Fe/Fe(OH) x heterostructure. Negligible decay in electrochemical surface areas of (Pt 0.9 Pd 0.1 ) 3 Fe intermetallic after a given accelerated durability test confirms the significant advantage in stability over Pt 3 Fe alloy. This work sheds light on the significance of ligand effects optimization and real-time tracing of the catalytic process to the structure−activity relationship establishment and subsequent catalyst designs.

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