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a b s t r a c tA TiO 2 organic sol was synthesised for the preparation of a compact TiO 2 layer on fluorine-doped tin oxide (FTO) glass by a dip-coating technique. The resultant thin film was used for the fabrication of dyesensitized solar cells (DSSCs). The compact layer typically has a thickness of ca. 110 nm as indicated by its SEM, and consists of anatase as confirmed by the XRD pattern. Compared with the traditional DSSCs without this compact layer, the solar energy-to-electricity conversion efficiency, short-circuit current and open-circuit potential of the DSSCs with the compact layer were improved by 33.3%, 20.3%, and 10.2%, respectively. This can be attributed to the merits brought by the compact layer. It can effectively improve adherence of TiO 2 to FTO surface, provide a larger TiO 2 /FTO contact area, and reduce the electron recombination by blocking the direct contact between the redox electrolyte and the conductive FTO surface.Crown

The redox potentials of 25 cyclic nitroxides from four different structural classes (pyrrolidine, piperidine, isoindoline, and azaphenalene) were determined experimentally by cyclic voltammetry in acetonitrile, and also via high-level ab initio molecular orbital calculations. It is shown that the potentials are influenced by the type of ring system, ring substituents and/or groups surrounding the radical moiety. For the pyrrolidine, piperidine, and isoindolines there is excellent agreement (mean absolute deviation of 0.05 V) between the calculated and experimental oxidation potentials; for the azaphenalenes, however, there is an extraordinary discrepancy (mean absolute deviation of 0.60 V), implying that their one-electron oxidation might involve additional processes not considered in the theoretical calculations. This recently developed azaphenalene class of nitroxide represents a new variant of a nitroxide ring fused to an aromatic system and details of the synthesis of five derivatives involving differing aryl substitution are also presented.

Single‐atom catalysts, which can maximize the utility of metal atoms, and at the same time achieve high catalytic performance, have attracted great interest in research. In this present study, 11 transition metal atoms supported on a graphdiyne (GDY) monolayer (TM@GDY, where TM represents a transition metal from Sc to Zn and Pt) as electrocatalysts are investigated by means of first‐principle calculations. It is found that the supported single atom is very stable at the corner of the acetylenic ring. These features can help in the realization of uniformly distributed and well‐ordered single atoms on GDY. Few composites viz Sc@GDY, Ti@GDY, V@GDY, Fe@GDY, and Pt@GDY display high catalytic activity toward hydrogen evolution reaction (HER). Especially for Ti@GDY and V@GDY, both C and TM are active sites which are the best HER catalysts among the studied composites. Moreover, Pt@GDY and Ni@GDY composites can be promising bifunctional electrocatalysts for water splitting [0.01 and 0.46 V for HER and oxygen evolution reaction (OER)] and metal–air‐battery (0.29 and 0.40 V for OER and oxygen reduction reaction) catalysts, respectively. This work demonstrates that GDY is indeed a promising single‐atom support which can be considered for the design of high activity and inexpensive multifunctional electrocatalysts for practical catalytic applications.

The effect of microwave modification of colloidal TiO2 suspensions under extended periods of treatment is presented. The nanoparticulate TiO2 is compared and contrasted to similar convection hydrothermally treated TiO2 and a commercial titania product, namely Degussa P25. Microwave-treated samples were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy to determine their physicochemical characteristics. Comparative surface area analyses were performed by N2 adsorption and calculated from a Brunauer-Emmett-Teller (BET) isotherm. The complementary techniques of XRD and TEM showed good correlation between observed and calculated particle sizes (by application of the Scherrer equation), with the material being highly crystalline anatase TiO2, as identified by XRD and Raman. This investigation identified that extended periods of microwave hydrothermal treatment do not greatly enhance the crystallinity and primary grain size. Treatment of >180 min has a negative effect on crystallite growth; however, treatment up to this time had a significant effect on the material's surface area. The limiting regime of Ostwald ripening for hydrothermal treatment is discussed in relation to the mechanism of microwave treatment, that is, rapid heating to temperature and extremely rapid rates of crystallization. The effect of these property modifications are further discussed in relation to photocatalytic and photoelectrochemical applications of TiO2 nanoparticles.

Titanium dioxide nanocrystals are an important commercial product used primarily in white pigments and abrasives, however, more recently the anatase form of TiO 2 has become a major component in electrochemical and photoelectrochemical devices. An important property of titanium dioxide nanocrystals for electrical applications is the degree of crystallinity. Numerous preparation methods exist for the production of highly crystalline TiO 2 particles. The majority of these processes require long reaction times, high pressures and temperatures (450-1400 uC). Recently, hydrothermal treatment of colloidal TiO 2 suspensions has been shown to produce quality crystalline products at low temperatures (v250 uC). In this paper we extend this idea utilising a direct microwave heating source. A comparison between convection and microwave hydrothermal treatment of colloidal TiO 2 is presented. The resulting highly crystalline TiO 2 colloids were characterised using Raman spectroscopy, XRD, TEM, and electron diffraction. The results show that the microwave treatment of colloidal TiO 2 gives comparable increases in crystallinity with respect to normal hydrothermal treatments while requiring significantly less time and energy than the hydrothermal convection treatment.

In this letter, we report the ability of the nanostructured aluminum Al 6063 alloy surfaces to inactivate the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). There was no recoverable viable virus after 6 h of exposure to the nanostructured surface, elucidating a 5-log reduction compared to a flat Al 6063 surface. The nanostructured surfaces were fabricated using wet-etching techniques which generated nanotextured, randomly aligned ridges approximately 23 nm wide on the Al 6063 alloy surfaces. In addition to the excellent mechanical resilience properties previously shown, the etched surfaces have also demonstrated superior corrosion resistance compared to the control surfaces. Such nanostructured surfaces have the potential to be used in healthcare environment such as hospitals and public spaces to reduce the surface transmission of SARS-CoV-2 and combat COVID-19.

A titanium organic sol was synthesized for the modification of conventional porous TiO 2 photoanodes for dye-sensitized solar cells (DSSCs). As a result, a compact thin TiO 2 film was superimposed on the porous TiO 2 structure as an efficient electron transport network, covering bare conducting substrate surface (FTO) and bridging gaps between TiO 2 nanoparticles, which was confirmed by scanning electron microscope (SEM) and transmission electron microscope (TEM). Dark current measurement suggested that the sol modified photoanode had a remarkably slower recombination rate of the photoelectrons due to the reduced bare FTO surface in comparison with the porous photoanode. The network facilitates the electron transfer in the DSSC process by removing the dead ends of electron pathways, connecting gaps along the electron pathways, and physically enlarging electron pathways, which can be demonstrated by the performance improvement of photocurrent and open-circuit potential. Consequently, the overall energy conversion efficiency of the DSSC was significantly enhanced by 28% after this simple and low-cost organic sol modification. The significant performance improvements observed from the organic sol modified DSSCs suggest that the proposed modification method is a promising alternative to the traditional TiCl 4 modification method.