Phosphorus‐Doped Perovskite Oxide as Highly Efficient Water Oxidation Electrocatalyst in Alkaline Solution

Abstract

1 wileyonlinelibrary.com evolution reaction (OER) is currently the limiting factor on the water splitting due to its sluggish kinetics involving the complex four-electron oxidation process. [3] To this end, the presence of an efficient OER electrocatalyst is essential to obtain an accelerated reaction rate. At present, precious metal-based iridium and ruthenium oxides (i.e., IrO 2 and RuO 2 ) are regarded as the OER catalysts benchmarks, [4] but their scarcity and high cost have hindered their wide-scale applications. IrO 2 and RuO 2 catalysts additionally show poor stability during long-term operation in alkaline solutions. [5] As such, tremendous efforts have been devoted to develop low-cost and earth-abundant alternative OER catalysts with high activity and good stability.Over the past few decades, due to their compositional and structural flexibility, precious metal-free perovskitetype oxides with a general formula of ABO 3 (A = alkaline-earth or rare-earth metals and B = transition metals) have attracted interests in various applications, e.g., solid oxide fuel cells (SOFCs), oxygen permeation membranes, metalair batteries, and supercapacitors. [6] Most recently, they were reported to also exhibit high OER activity in an alkaline solution. [7] Rossmeisl group and Koper group theoretically calculated that SrCoO 3 parent oxide would deliver the highest OER activity among LaMO 3 and SrMO 3 (M = transition metals) parent oxides via density functional theory calculations. [8] Shao-Horn and co-workers reported that one of the Developing cost-effective and efficient electrocatalysts for oxygen evolution reaction (OER) is of paramount importance for the storage of renewable energies. Perovskite oxides serve as attractive candidates given their structural and compositional flexibility in addition to high intrinsic catalytic activity. In a departure from the conventional doping approach utilizing metal elements only, here it is shown that non-metal element doping provides an another attractive avenue to optimize the structure stability and OER performance of perovskite oxides. This is exemplified by a novel tetragonal perovskite developed in this work, i.e., SrCo 0.95 P 0.05 O 3-δ (SCP) which features higher electrical conductivity and larger amount of O 2 2− /O − species relative to the non-doped parent SrCoO 3-δ (SC), and thus shows improved OER activity. Also, the performance of SCP compares favorably to that of well-developed perovskite oxides reported. More importantly, an unusual activation process with enhanced activity during accelerated durability test (ADT) is observed for SCP, whereas SC delivers deactivation for the OER. Such an activation phenomenon for SCP may be primarily attributed to the in situ formation of active A-site-deficient structure on the surface and the increased electrochemical surface area during ADT. The concept presented here bolsters the prospect to develop a viable alternative to precious metal-based catalysts.

High‐Performance Platinum‐Perovskite Composite Bifunctional Oxygen Electrocatalyst for Rechargeable Zn–Air Battery

“…X-ray photo electron spectroscopy, X-ray absorption near-edge structure, and extended X-ray absorption fine structure experiments demonstrate that the superior performance is due to the strong electronic interaction between Pt and SCFP that arises as a result of the rapid electron transfer via the PtOCo bonds as well as the higher concentration of surface oxygen vacancies. [14] Building on this previous work, here we synthesized the Fe-doped analogue of the SCP, Sr(Co 0.8 Fe 0.2 ) 0.95 P 0.05 O 3−δ (SCFP), via solid-state reaction route. Undoubtedly, this work provides an efficient approach for developing low-cost and highly active catalysts for wider application of electrochemical energy devices.…”

Fabrication of a Mo‐Doped Strontium Cobaltite Perovskite Hybrid Supercapacitor Cell with High Energy Density and Excellent Cycling Life

“…Even at ah igh power delivery rate (6600 Wkg À1 ), the hybrid cell maintains ah igh energy density (33 Wh kg À1 )w ith ac harging time of only 20.7 s. To our knowledge, no pior study has demonstrated the charge storage characteristics of SCM for supercapacitort echnologies. [31] The deconvoluted spectrum of Co ( Figure 1d)s uggests the presence of cobalt in two oxidation states,n amely Co 2 + and Co 3 + .F rom the core level spectrum, two major peaks observed around 781 and 779.6 eV are attributed to Co 2 + and Co 3 + 2p 3/2 ,r espectively. [24] In contrast, all the diffraction peaks of SC matched with the hexagonal phase ( Figure S1 ai nt he Supporting Information) [36] of strontium cobaltite.…”

Super‐Exchange Interaction Induced Overall Optimization in Ferromagnetic Perovskite Oxides Enables Ultrafast Water Oxidation

“…So far, donor or electron doping of highly charged cations into SrCoO 3− δ have been widely employed as effective way to enhance the electrical conductivity. For example, Zhu et al reported that P 5+ doped SrCo 0.95 P 0.05 O 3− δ perovskite exhibits a stable tetragonal structure and features much higher electrical conductivity relative to SC, thus displaying improved OER activity 13a. Some other highly charged cations (e.g., Nb 5+ , Ta 5+ , Sc 3+ , Ti 4+ ) was also used to stabilize the Co sites in SC, but these doped cations themselves are inert to OER, which will not help further activity enhancement to some extent.…”