Utilizing ion leaching effects for achieving high oxygen-evolving performance on hybrid nanocomposite with self-optimized behaviors

Abstract

Ion leaching from pure-phase oxygen-evolving electrocatalysts generally exists, leading to the collapse and loss of catalyst crystalline matrix. Here, different from previous design methodologies of pure-phase perovskites, we introduce soluble BaCl 2 and SrCl 2 into perovskites through a self-assembly process aimed at simultaneously tuning dual cation/anion leaching effects and optimizing ion match in perovskites to protect the crystalline matrix. As a proofof-concept, self-assembled hybrid Ba 0.35 Sr 0.65 Co 0.8 Fe 0.2 O 3-δ (BSCF) nanocomposite (with BaCl 2 and SrCl 2) exhibits the low overpotential of 260 mV at 10 mA cm-2 in 0.1 M KOH. Multiple operando spectroscopic techniques reveal that the pre-leaching of soluble compounds lowers the difference of interfacial ion concentrations and thus endows the host phase in hybrid BSCF with abundant time and space to form stable edge/face-sharing surface structures. These self-optimized crystalline structures show stable lattice oxygen active sites and short reaction pathways between Co-Co/Fe metal active sites to trigger favorable adsorption of OH − species.

Engineering Self‐Reconstruction via Flexible Components in Layered Double Hydroxides for Superior‐Evolving Performance

“…The Tafel plots in Figure 3d show that the NiFeMo-SR has a smaller Tafel slope of 32 mV dec −1 compared with those of the NiFeC-SR (35 mV dec −1 ) and IrO 2 (79 mV dec −1 ), verifying its superior catalytic kinetics. This OER performance is among the best for TM-based LDHs and also superior to those of most recently reported non-precious OER catalysts in alkaline media (Figure 3f and Table S1, Supporting Information), such as NiFe-LDHs, [45] NiFeO x H y , [46] hybrid BiCrCoFeO, [47] and Mo 2 C/Mo 2 N catalysts. [48] We estimated the electrochemically active surface area (ECSA) for two reference catalysts before and after ECSR activation by using double-layer capacitance (C dl ) from CV curves in the range of no Faradaic dynamics (Figure S5, Supporting Information).…”

Fast operando spectroscopy tracking in situ generation of rich defects in silver nanocrystals for highly selective electrochemical CO2 reduction

“…Recently, Wang et al suggested that the change of CN for metal atoms from EXAFS data could be helpful in the analysis of the defect concentration 60 . The fitting of CN from EXAFS data has been successfully reported in our previous study 63 . Based on the knowledge, we introduce a concept, the relative concentration of defects (RC d ), to perform a quantification analysis.…”

Self-standing 3D nanoporous Ag2Al with abundant surface oxygen species facilitating oxygen electroreduction for efficient hybrid Zn battery

“…S11. Because the mixture phase has less ORR activity than Ag 2 Al with abundant oxygen species, and the ORR response would tend to be stable after the residual Al removed to form the stable intermetallic compound Ag 2 Al under the biased condition, which could be considered as a self-optimized behavior [43]. Also, this is an evidence that the intermetallic Ag 2 Al could contribute to ORR activity.…”