Transition metal phosphides have been investigated heavily as hydrogen evolution reaction (HER) catalysts. One of the most active transition metal phosphides, CoP, has been tested for its stability and operability under mild conditions that it may be exposed to in its applications (photoelectrochemistry and artificial photosynthesis). Surface-interrogation scanning electrochemical microscopy (SI-SECM) revealed that CoP HER catalyst is vulnerable to oxidation (by oxygen and chemical oxidants). The degradation mechanism was shown to be surface oxidation by dioxygen, followed by acid etching of the oxidized layer. The compositional integrity (unity ratio of cobalt and phosphorus) was maintained throughout the film decomposition progress. (Graph Presented).
Bibliographical noteFunding Information:
The authors thank Dr. Juan F. Callejas and Prof. Raymond E. Schaak for helpful discussions during the inception of the project. This work was supported by NSF under the NSF Center (CHE-1305124) and the Welch Foundation (F-0021). H.S.A. was partially supported by Basic Science Research Program through the National Research Foundation (NRF) of Korea funded by the Ministry of Science, ICT & Future Planning (NRF-2017R1C1B2011074) and by the Institute for Basic Science (Project Code IBS-R026-D1).
All Science Journal Classification (ASJC) codes
- Analytical Chemistry