Nickel cobaltite, a low cost and an environmentally friendly supercapacitive material, is deposited as a thin nanostructure of 3–5 nm nanocrystals into carbon aerogels, a mesoporous host template of high specific surface areas and high electric conductivities, with a two‐step wet chemistry process. This nickel cobaltite/carbon aerogel composite shows ultrahigh specific capacitances of around 1700 F g−1 at a scan rate of 25 mV s−1 within a potential window of −0.05 to 0.5 V in 1 M NaOH solutions. The composite also possesses an excellent high rate capability manifested by maintaining specific capacitances above 800 F g−1 at a high scan rate of 500 mV s−1, and an outstanding cycling stability demonstrated by a negligible 2.4% decay in specific capacitances after 2000 cycles. The success is attributable to the fuller utilization of nickel cobaltite for pseudocapacitance generation, made possible by the composite structure enabling well exposed nickel cobaltite to the electrolyte and easy transport of charge carriers, ions, and electrons, within the composite electrode.

A facile, one-step, template-less, surfactant-free hydrothermal process, using a metal salt as the precursor, is developed to prepare submicrometer sized mesoporous TiO 2 nanoparticle aggregates (NPGs). The as-prepared TiO 2 NPGs are crystalline of the anatase phase, with a high specific surface area of 166 m 2 /g, an average pore size of 8.9 nm, and an average NPG size of 840 nm. With these NPGs, a new form of composite photoanode, consisting of the mesoporous TiO 2 NPGs and xerogels, is proposed for high efficiency dye-sensitized solar cells (DSSCs). TiO 2 xerogels are incorporated into the TiO 2 NPGs layer with an impregnation process to form the TiO 2 NPGs/xerogels composite. A high power conversion efficiency of 8.41% is achieved for DSSCs based on the TiO 2 NPGs/xerogels composite photoanode, representing a 38% efficiency boost over the efficiency of 6.11% achieved with a P25 TiO 2 based cell. The success of the present composite TiO 2 nanostructure can be attributed to the effective utilization of the inter-NPG space with the infiltration of the TiO 2 xerogels, the excellent structural connectivity within and across the NPG and xerogel domains for fast electron transport, the high specific surface areas of both the NPGs and xerogels for providing abundant dye adsorption for generation of photoinduced electrons, the formation of a TiO 2 xerogel blocking layer on top of the photoanode substrate, and the submicrometer size of the NPGs for much improved light harvesting efficiency. This new type of composite photoanode, different from the 0D/1D nanostructure based ones, proves effective by taking structural advantages from both constituent nanostructures, the mesoprous NPGs and xerogels, and opens up a new way of thinking in the structural design of the photoanodes.

No abstract

Cu2O‐decorated mesoporous TiO2 beads (MTBs) are developed as a low‐cost, highly efficient photocatalyst for H2 production. MTBs with a high specific surface area of 189 m2 g−1, a large pore volume of 0.43 cm3 g−1 and a suitable pore size of 8.9 nm are decorated with band‐structure‐matched Cu2O nanocrystals through a simple, fast and low‐cost chemical bath deposition process. The Cu2O nanocrystals serve as an electron–hole separation centre to promote H2 evolution. Under optimal operation conditions, an ultra‐high specific H2 evolution rate of 223 mmol h−1 g−1 is achieved. The success is attributed to the structural advantages of the MTBs of high specific surface areas, large pore volumes and suitable pore sizes together with the much improved electron–hole separation and light utilisation of the Cu2O‐decorated MTBs. The H2 evolution rates achieved with the Cu2O‐decorated MTBs are one order of magnitude higher than those achieved by commercial P25 TiO2.

Background: Membrane vesicles (MVs) released from various cells are associated with human diseases. Results: MVs isolated from human serum induce the formation of mineralo-organic nanoparticles in culture. Conclusion: MVs represent a nucleating factor that promotes the formation of mineralo-organic nanoparticles and the precipitation of mineral deposits in body fluids. Significance: The ectopic precipitation of carbonate apatite deposits in body fluids and tissues may be initiated in part by MVs.