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α-Phase hematite photoelectrodes can split water. This material is nontoxic, inexpensive, and chemically stable; its low energy gap of 2.3 eV absorbs light with wavelengths lower than 550 nm, accounting for approximately 30% of solar energy. Previously, we reported polyhedral pseudocubic α-Fe2O3 nanocrystals using a facile hydrothermal route to increase spatial charge separation, enhancing the photocurrent of photocatalytic activity in the water-splitting process. Here, we propose a p-n junction structure in the photoanode of pseudocubic α-Fe2O3 to improve short carrier diffusion length, which limits its photocatalytic efficiency. We dope Zn on top of an Fe2O3 photoanode to form a layer of p-type semiconductor material; Sn is doped from the FTO substrate to form a layer of n-type semiconductor material. The p-n junction, n-type Fe2O3:Sn and p-type Fe2O3:Zn, increase light absorption and charge separation caused by the internal electric field in the p-n junction. [ABSTRACT FROM AUTHOR]

Silver nanowires (NWs) were successfully synthesized in high yield in cationic surfactant solutions of cetyltrimethylammonium bromide (CTAB) with hyaluronan (HA) additive. Most of the NWs had diameter of 10-30 nm and length of more than tens of microns. The carboxylate group of HA provides a stronger electrostatic interaction with the cationic heads of CTAB and promotes formation of lengthened cylindrical micelles. Silver ions were reduced by addition of ascorbic acid and heating, and the embryonic silver seeds promoted growth of silver NWs along the one-dimensional direction of the cylindrical micelles. Presence of any gold nanoparticles or nanorods in the solution can prominently inhibit the formation of silver seeds and decrease the yield of silver NWs. [ABSTRACT FROM AUTHOR]

Au-Ag core-shell (Au@Ag) nanobars could be synthesized from gold nanorod (NR) seeds with cysteine additives by a two-step process of reaction temperatures. The lateral sides of gold NRs surrounded by surfactant bilayers render cysteine additives binding on both ends of the NRs, and restricted silver deposition to their lateral sides at room temperature. Further, silver deposition can take place at first on the pre-formed silver layers on the lateral sides at higher temperatures and finally resulted in the formation of Au@Ag nanobars in which gold NRs are in the corner positions of the nanobars and their longitudinal axes parallel to the longer sides of the nanobars. [ABSTRACT FROM AUTHOR]