| 초록 |
Converting water to O2 and H2 has been regards as a central chemistry of energy conversion technology. Indeed, water splitting is evaluated as highly economical way for providing a sustainable source of hydrogen to many renewable-energy technologies. Water-alkali electrolysis can be viewed as a combination of two half-cell reaction: the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) which occur in cathode and anode, respectively. In practice, large-scale application for the electrochemical production of hydrogen form water splitting is limited by lack of stable electrode materials and high overpotentials of HER and OER at alkaline media. Described herein is investigation of a new transition metal-based oxygen evolution catalyst generated in-situ from transition metal phosphide (TMP) nanoparticles. In this work, we have elucidated that the present TMP nanoparticles, alkaline hydrogen-evolving materials at cathodic potentials, are reveals to experience unique transformation upon anodic potential cycling in alkaline electrolyte, yielding efficient and robust catalytic environments toward oxygen evolution reaction. Our extensive characterization studies disclose that the metamorphosed catalyst bear porous and nanowed-like dispersed morphologies along with unique microscopic environments mainly comprised of discrete TMP-oxo/hydro molecular units within phosphate-enriched amorphous network. Not only excellent OER efficiency favorably comparable to a precious iridium catalyst and conventional transition metal oxide based materials, but also remarkable durability was achieved by the in-situ transformed catalyst. Along with the present catalyst, 12 hr bulk electrolysis continuously operating at high current density is completely tolerable. The present work highlights that control of restructuring behavior upon andic potentials can be available in nanopaticular system by designing its precursive stable to be coupled with possible ligating species. |
