SnP 2 O 7 -based proton conductors were characterized by Fourier transform infrared spectroscopy ͑FTIR͒, temperature-programmed desorption ͑TPD͒, X-ray diffraction ͑XRD͒, and electrochemical techniques. Undoped SnP 2 O 7 showed overall conductivities greater than 10 −2 S cm −1 in the temperature range of 75-300°C. The proton transport numbers of this material at 250°C under various conditions were estimated, based on the ratio of the electromotive force of the galvanic cells to the theoretical values, to be 0.97-0.99 in humidified H 2 and 0.89-0.92 under fuel cell conditions. Partial substitution of In 3+ for Sn 4+ led to an increase in the proton conductivity ͑from 5.56 ϫ 10 −2 to 1.95 ϫ 10 −1 S cm −1 at 250°C, for example͒. FTIR and TPD measurements revealed that the effects of doping on the proton conductivity could be attributed to an increase in the proton concentration in the bulk Sn 1−x In x P 2 O 7 . The deficiency of P 2 O 7 ions in the Sn 1−x In x P 2 O 7 bulk decreased the proton conductivity by several orders of magnitude, which was explained as due to a decrease in the proton mobility rather than the proton concentration. The mechanism of proton incorporation and conduction is examined and discussed in detail.

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Experimental setups to produce and to monitor model membranes have been successfully used for decades and brought invaluable insights into many areas of biology. However, they all have limitations that prevent the full in vitro mimicking and monitoring of most biological processes. Here, a suspended physiological bilayer‐forming chip is designed from 3D‐printing techniques. This chip can be simultaneously integrated to a confocal microscope and a path‐clamp amplifier. It is composed of poly(dimethylsiloxane) and consists of a ≈100 µm hole, where the horizontal planar bilayer is formed, connecting two open crossed‐channels, which allows for altering of each lipid monolayer separately. The bilayer, formed by the zipping of two lipid leaflets, is free‐standing, horizontal, stable, fluid, solvent‐free, and flat with the 14 types of physiologically relevant lipids, and the bilayer formation process is highly reproducible. Because of the two channels, asymmetric bilayers can be formed by making the two lipid leaflets of different composition. Furthermore, proteins, such as transmembrane, peripheral, and pore‐forming proteins, can be added to the bilayer in controlled orientation and keep their native mobility and activity. These features allow in vitro recapitulation of membrane process close to physiological conditions.