Competitive hydrogen evolution and multiple proton-coupled electron transfer reactions limit photoelectrochemical CO2 reduction in aqueous electrolyte. Here, oxygen-terminated lightly boron-doped diamond (BDDL) thin films were synthesized as a semiconductor electron source to accelerate CO2 reduction. However, BDDL alone could not stabilize the intermediates of CO2 reduction, yielding a negligible amount of reduction products. Silver nanoparticles were then deposited on BDDL because of their selective electrochemical CO2 reduction ability. Excellent selectivity (estimated CO:H2 mass ratio of 318:1) and recyclability (stable for five cycles of 3 h each) for photoelectrochemical CO2 reduction were obtained for the optimum silver nanoparticle-modified BDDL electrode at −1.1 V vs. RHE under 222-nm irradiation. The high efficiency and stability of this catalyst are ascribed to the in situ photoactivation of the BDDL surface during the photoelectrochemical reaction. The present work reveals the potential of BDDL as a high-energy electron source for use with co-catalysts in photochemical conversion.

Ozonated water was investigated using a conventional UV-Vis spectrophotometer. We compared the UV absorption spectra of ozone (O 3 ) in water generated by either O 2 or air plasma bubbling method. The results noted that the observing the entire absorption spectrum is important for understanding the composition of ozonated water. Using an in-situ with an O 2 plasma bubbling in water we monitored the time-resolved UV absorption spectrum of the ozonated water. It is well known that a typical UV absorption spectrum of ozonated water contains a broad absorption peak at 260 nm and a shoulder below 220 nm. In our time-resolved measurement, however, it initially contained a broad absorption at short wavelength range below 210 nm considerably from dissolved O 2 . As increase of the ozonation time, it noted that the absorption spectrum indicated the presence of high concentration of H 2 O 2 and O 2 as well as relatively lower concentration of O 3 .

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Materials fabricated with unsintered hydroxyapatite/poly‐l‐lactic acid (uHA/PLLA) exhibit biological activity and biocompatibility, but are also hydrophobic. This hydrophobicity limits the ability of cells or tissues to adhere to the surface of the material and thereby prevents the materials from exhibiting effective biological activity. In this study, we examined the effects of ultraviolet (UV) treatment on the hydrophobicity of uHA/PLLA. We compared the contact angle, mechanical strength, cell attachment, and cell differentiation capacity between untreated uHA/PLLA and uHA/PLLA treated with UV light. The contact angle of UV‐treated uHA/PLLA was significantly reduced compared with that of untreated uHA/PLLA. However, there were no differences in mechanical strength between untreated uHA/PLLA and UV‐treated uHA/PLLA. Notably, the ability of cells to adhere to UV‐treated uHA/PLLA was significantly increased compared with that of untreated uHA/PLLA. Similarly, there were significant differences between UV‐treated uHA/PLLA and untreated uHA/PLLA in alkaline phosphatase assays. These findings demonstrated that UV irradiation of uHA/PLLA improved the surface hydrophilicity without changing the mechanical strength of the material; thus, UV treatment of uHA/PLLA may facilitate the use of this material in biomedical applications. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 191–200, 2018.

There is a need for highly efficient photocatalysts, particularly for water purification. In this study, we fabricated a mesoporous TiO2 thin film on a boron-doped diamond (BDD) layer by a surfactant-assisted sol-gel method, in which self-assembled amphiphilic surfactant micelles were used as an organic template. Scanning electron microscopy revealed uniform mesopores, approximately 20 nm in diameter, that were hexagonally packed in the TiO2 thin film. Wide-angle X-ray diffraction and Raman spectroscopy clarified that the framework crystallized in the anatase phase. Current–voltage (I–V) measurements showed rectification features at the TiO2/BDD heterojunction, confirming that a p–n hetero-interface formed. The as-synthesized mesoporous TiO2/BDD worked well as a photocatalyst, even with a small volume of TiO2 (15 mm × 15 mm × c.a. 1.5 µm in thickness). The use of deep UV light (λ = 222 nm) as a light source was necessary to enhance photocatalytic activity, due to photo-excitation occurring in both BDD and TiO2.