The kinetics and mechanisms of many catalytic surface reactions depend on the atomic level structure of surfaces. Detailed study and understanding of the influence of surface structure on a given reaction is experimentally arduous. The space of possible surface orientations spans a two-dimensional continuum. A detailed study of structure sensitive surface chemistry requires preparation and study of many different single crystal substrates, each with a different orientation. A new high-throughput methodology has been developed based on the use of Surface Structure Spread Single Crystals (S4C), spherically curved single crystals that expose a continuous distribution of different crystallographic planes across their surfaces. These S4C surfaces are being studied using surface analysis tools capable of spatially-resolved measurements that can sample the continuous space of surface orientations.

 

Six copper S4C surfaces have been produced in-house: three low Miller index centered surfaces, (100), (110), and (111); and three high Miller index surfaces, (821), (861), and (432). Each surface has been chosen and spherically curved so that the complete set of surfaces spans the entire stereographic triangle. The surfaces have been characterized using laser profilometry and oriented using x-ray diffraction and low energy electron diffraction. A benefit of the S4C surfaces is that they are naturally chiral, forming regions of either R- or S- chirality. The surface chemistry of a chiral molecule, such as tartaric acid, on a naturally chiral surface can be enantiospecific. Tartaric acid decomposition from copper surfaces shows very high enantioselectivity due to its highly nonlinear surface explosion kinetics. The nature and magnitude of the enantioselectivity of tartaric acid decomposition across the stereographic triangle is not currently well-understood. Copper S4C surfaces provide an opportunity to study tartaric acid decomposition on virtually all possible copper surface structures. This research is the first attempt to map surface enantioselectivity for any compound across the entire stereographic triangle in high detail.