On-board fuel cell technology requires proton conducting materials with high conductivity not only at intermediate temperatures for work but also at room temperature and even at subzero temperature for startup when exposed to the colder climate. To develop such materials is still challenging because many promising candidates for the proton transport on the basis of extended microstructures of water molecules suffer from significant damage by heat at temperatures above 80 °C or by freeze below -5 °C. Here we show imidazole loaded tetrahedral polyimides with mesopores and good stability (Im@Td-PNDI 1 and Im@Td-PPI 2) exhibiting a high anhydrous proton conductivity over a wide temperature range from -40 to 90 °C. Among all anhydrous proton conductors, the conductivity of 2 is the highest at temperatures below 40 °C and comparable with the best materials, His@[Al(OH)(1,4-ndc)]n and [Zn3(H2PO4)6(H2O)3](Hbim), above 40 °C.

Gas-generating catalysis is important to many energy-related research fields, such as photocatalytic water splitting, water electrolysis, etc. The technique of single-nanoparticle catalysis is an effective way to search for highly active nanocatalysts and elucidate the reaction mechanism. However, gas-generating catalysis remains difficult to investigate at the single-nanoparticle level because product gases, such as H and O, are difficult to detect on an individual nanoparticle. Here, we successfully find that nanobubbles can be used to study the gas-generating catalysis, i.e., H generation from formic acid dehydrogenation on a single Pd-Ag nanoplate, with a high time resolution (50 ms) via dark-field microscopy. The research reveals that the nanobubble evolution process includes nucleation time and lifetime. The nucleation rate of nanobubbles is proportional to the catalytic activity of a single nanocatalyst. The relationship between the catalytic activity and the nucleation rate is quantitatively described by a mathematical model, which shows that an onset reaction rate (r) exists for the generation of nanobubbles on a single Pd-Ag nanoplate. The research also reveals that a Pd-Ag nanoplate with larger size usually has a higher activity. However, some large-sized ones still have low activities, indicating the size of the Pd-Ag nanoplate is not the only key factor for the activity. Notablely, further research shows that Pd content is the key factor for the activity of single Pd-Ag nanoplates with similar size. The methodology and knowledge acquired from this research are also applicable to other important gas-generating catalysis reactions at the single-nanoparticle level.

Great improvement in a fuel cell was achieved by constructing three fast pathways using a highly dense, well-ordered, and cone-shaped Nafion array.