Pengzhan Sun

Pengzhan Sun has been focusing on the research of molecular and ionic transport in two-dimensional (2D) membrane systems with precisely constructed channels offering strong confinement and solving basic scientific problems related to 2D membrane separation research.

Pengzhan developed new devices and technologies aiming at increasing the sensitivity of detecting molecular flows across defect-free graphene and other 2D crystals. This innovation has led to a detection limit of s billion times lower than previously thought. The ultimate sensitivity has allowed the discovery of many new physics regarding the research on molecular transport under strong confinement. He observed discernible hydrogen-gas permeation through defect-free graphene membranes, despite the latter being completely impermeable to the smaller and generally much more permeating helium atoms​.

Pengzhan developed a new and precise perforation technique, which involved a short-time exposure of the graphene membrane to a low-energy electron beam. Using the same monocrystalline container technique, he was able to study gas transport through individual graphene pores. For different gases such as hydrogen and methane with a size difference of only 25%, its transport selectivity is higher than all known membranes. Trying to understand the physics behind the unexpected hydrogen-gas permeation through graphene, Pengzhan designed delicate experiments and found that unlike graphite, nanorippled graphene exhibits a strong activity with respect to splitting molecular hydrogen, which is comparable to that of metallic and other known catalysts. These findings provide new understanding for the permeability of graphene from a fundamental cognition level and also emphasize an unexpectedly high catalytic activity of non-flat graphene.

The key knowledge learnt from these studies would no doubt be important from a fundamental perspective and for the development of new technologies involving hydrogen, molecular sieving, catalysis for energy, environment, and chemical engineering applications​.