03019nas a2200301   4500008004100000022001400041245014600055210006900201260000900270300001600279490000700295520196300302653000902265653003202274653001802306653002302324653003802347653003002385653002502415100001802440700001602458700002202474700002002496700002702516700002802543700002502571856012102596       2023                        eng d  a1936-085100aDistortion-induced interfacial charge transfer at single cobalt atom secured on ordered intermetallic surface enhances pure oxygen production0 aDistortioninduced interfacial charge transfer at single cobalt a  cNOV   a23169-231800 v173 a<p>In this work, atomic cobalt (Co) incorporation into the Pd2Ge intermetallic lattice facilitates operando generation of a thin layer of CoO over Co-substituted Pd2Ge, with Co in the CoO surface layer functioning as single metal sites. Hence the catalyst has been titled Co-1-CoO-Pd2Ge. High-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, and X-ray absorption spectroscopy confirm the existence of CoO, with some of the Co bonded to Ge by substitution of Pd sites in the Pd2Ge lattice. The role of the CoO layer in the oxygen evolution reaction (OER) has been verified by its selective removal using argon sputtering and conducting the OER on the etched catalyst. In situ X-ray absorption near-edge structure and extended X-ray absorption fine structure spectroscopy demonstrate that CoO gets transformed to CoOOH (Co3+) in operando condition with faster charge transfer through Pd atoms in the core Pd2Ge lattice. In situ Raman spectroscopy depicts the emergence of a CoOOH phase on applying potential and shows that the phase is stable with increasing potential and time without getting converted to CoO2. Density functional theory calculations indicate that the Pd2Ge lattice induces distortion in the CoO phase and generates unpaired spins in a nonmagnetic CoOOH system resulting in an increase in the OER activity and durability. The existence of spin density even after electrocatalysis is verified from electron paramagnetic resonance spectroscopy. We have thus successfully synthesized intermetallic supported CoO during synthesis and rigorously verified the role played by an intermetallic Pd2Ge core in enhancing charge transfer, generating spin density, improving electrochemical durability, and imparting mechanical stability to a thin CoOOH overlayer. Differential electrochemical mass spectrometry has been explored to visualize the instantaneous generation of oxygen gas during the onset of the reaction.</p>
10aDEMS10ainterfacial charge transfer10aIntermetallic10along-termstability10aoperando spectroscopic techniques10aOxygen Evolution Reaction10astructuraldistortion1 aMondal, Soumi1 aRiyaz, Mohd1 aBagchi, Debabrata1 aDutta, Nilutpal1 aSingh, Ashutosh, Kumar1 aVinod, Chathakudath, P.1 aPeter, Sebastian, C.  uhttps://library.ncl.res.in/content/distortion-induced-interfacial-charge-transfer-single-cobalt-atom-secured-ordered