The design of appropriate composite materials with unique surface structures is an important strategy to achieve ideal chemical gas sensing. In this paper, efficient and selective detection of formaldehyde vapor has been realized by a gas sensor based on porous GaInO nanofibers assembled by small building blocks. By tuning the Ga/In atomic ratios in the materials, crystallite phase, nanostructure, and band gap of as-obtained GaInO nanofibers can be rationally altered. This further offers a good opportunity to optimize the gas sensing performances. In particular, the sensor based on porous GaInO nanofibers assembled by small nanoparticles (∼4.6 nm) exhibits best sensing performances. Toward 100 ppm formaldehyde, its highest response (R/R = 52.4, at 150 °C) is ∼4 times higher than that of the pure InO (R/R = 13.0, at 200 °C). Meanwhile, it has superior ability to selectively detect formaldehyde against other interfering volatile organic compound gases. The significantly improved sensing performance makes the GaInO sensor very promising for selective detection of formaldehyde.

Despite the superior oxygen evolution electrocatalytic activity of metal-selenide nanostructures, especially when compared with their oxide counterparts, the origin behind their excellent activity remains unclear.

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The design of one-dimensional titania with tunable structural hierarchy holds exciting implications for applications such as optoelectronics, sensing and catalysis. Here, we report a general precursor strategy for one-dimensional titania with surface nanoprotrusion and tunable hierarchical structures realized via a titanate route using electrospun titania fibers as precursors. One-dimensional hierarchical hollow titanate (1D-HHT) was first fabricated under mild alkaline hydrothermal conditions from electrospun amorphous TiO 2 precursors. The time-dependent evolution of 1D-HHT has been investigated in detail. The concerted effect of alkaline etching and Ostwald ripening is responsible for the surface nanoprotrusion and modulation of structural hierarchy. Anatase TiO 2 with the same hierarchical structures can be obtained using controlled calcination. The as-fabricated one-dimensional titania with varying levels of structural hierarchy exhibits about 1.3-1.5 times higher power conversion efficiency than commercial P25 as a photoanode material for dye-sensitized solar cells (DSSCs). The current work may be extended for more functional TiO 2 -based materials with tunable structural hierarchy and could widen the application range of electrospinning technology for one-dimensional hierarchical structures.