S-termination effects for the catalytic activities of Pd on GaN(0001) surfaces

摘要

A S-terminated GaN(0001) substrate covered with catalytically active Pd nanoparticles (PdNP) serves as a treatable and green chemical catalyst for various cross-coupling reactions. The role of S in the formation of PdNP has been studied so far, but the effect on the catalytic activity has not been investigated. In this study, we investigate the role of S-termination during the Mizoroki-Heck reaction from the view point of the stability of PdNP and the yield in repeated reactions. PdNP are formed on both S-terminated GaN(0001) surface and non-terminated one, and their catalytic activities are compared when the quantity of PdNP is subminimal and excessive. It is found that S-termination serves as a binder of PdNP on GaN(0001) surface, resulting in the self-regulation of PdNP leaching.