Defect Pyrochlore-Type Mott–Schottky Photocatalysts for Enhanced Ammonia Synthesis at Low Pressure

The ambient ammonia synthesis coupled with distributed green hydrogen production technology can provide promising solutions for low-carbon NH₃ production and H₂ storage. Herein, we reported Ru-loaded defective pyrochlore K₂Ta₂O_6−x with remarkable visible-light absorption and a very low work function, enabling effective visible-light-driven ammonia synthesis from N₂ and H₂ at low pressure down to 0.2 atm. The photocatalytic rate was 2.8 times higher than that of the best previously reported photocatalyst and the photo-thermal rate at 425 K was similar to that of Ru-loaded black TiO₂ at 633 K. Compared to perovskite-type KTaO_3−x with the same composition, the pyrochlore exhibited a 3.7-fold increase in intrinsic activity due to a higher photoexcited charge separation efficiency and a higher conduction band position. The interfacial Schottky barrier and spontaneous electron transfer between K₂Ta₂O_6−x and Ru further improve photoexcited charge separation and accumulate energetic electrons to facilitate N₂ activation.     

Raman spectral analysis of renal tissue: a novel application

Renal cell carcinoma (RCC) accounts for 85% of all primary renal cancers. The definitive diagnosis of RCC relies exclusively on the subjective pathological interpretation of the surgical specimen. In this study, we aimed to analyze renal tissue using objective Raman spectroscopy (RS). We obtained 15 pairs of RCC (T) and corresponding normal renal parenchymal tissues (N) from our biobank. There are three subtypes of RCC: clear cell RCC (ccRCC), papillary RCC (pRCC), and chromophobe RCC (cRCC). Five pairs of tissue of each subtype were enrolled. Fresh‐frozen sliced tissues were used for the RS detection. The Raman spectra between T and N were compared and analyzed using partial least squares (PLS) regression. Data for a total of 55 T and 58 N analyzable RS samples were obtained. The spectra were normalized by dividing the intensity of the characteristic peak at 1003 cm⁻¹ using phenylalanine's Raman peak. After further analysis with PLS, the sensitivity and specificity for discriminating T from N were 95% and 93%, respectively. The RCC subtypes can be discriminated at an accuracy of 72% for ccRCC, 88% for cRCC, and 86% for pRCC. This study demonstrates the feasibility of analyzing renal tissue using RS. RS, with its advantages of easy and objective tissue assessment, may be applied to aid intraoperative decision making and pathological tissue assessment. Copyright © 2014 John Wiley & Sons, Ltd.