Surface Defect Engineering on Perovskite Oxides as Efficient Bifunctional Electrocatalysts for Water Splitting

Abstract

The design of high-performance and cost-effective electrocatalysts for water splitting is of prime importance for efficient and sustainable hydrogen production. In this work, a surface defect engineering method is developed for optimizing the electrocatalytic activity of perovskite oxides for water electrolysis. A typical ferrite-based perovskite oxide material La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF) is used and regulated by selective acid etching. The optimal parameters for the surface treatment are identified. An efficient bifunctional perovskite oxide, denoted LSCF-30, is prepared by selectively corroding the A-site Sr element in the surface region, which is found to not only increase the exposure and decrease the coordination of B-site metals but also effectively modulate the electronic structure of these metals. The crystal lattice of the perovskite bulk is kept constant during surface engineering, which ensures the structural stability of the perovskite catalyst. The findings demonstrate an effective strategy of surface defect engineering in enhancing the performance of perovskite oxide electrocatalysts for water splitting.

Puffing ultrathin oxides with nonlayered structures

“…S27, B and C). This value is also comparable or superior to recently reported perovskitebased catalysts (table S4) (44)(45)(46)(47)(48)(49)(50)(51)(52)(53)(54)(55)(56). The mass activity of LFO at 1.55 V [versus (reversible hydrogen electrode) RHE] reaches 18.21 A g oxide −1 , which is also better than those of LMO (8.48 A g oxide −1 ), GFO (7.60 A g oxide −1 ), LCO (5.20 A g oxide −1 ), GMO (5.17 A g oxide −1 ), and GCO (4.20 A g oxide −1 ) (fig.…”

Recent Advances in Perovskite Catalysts for Efficient Overall Water Splitting

“…Great research efforts have been devoted to optimizing the performance of perovskite oxides, among which the defect engineering approach has proven its effectiveness in improving the intrinsic activity by regulating the electronic structure and inducing vacancy formation [16,122]. For ABO 3 perovskite oxides, the A/B cation ratio deviates from 1 within a certain range (0.9~1.1), and the structure can remain stable due to the high structural tolerance of the perovskite lattice [123].…”

“…However, their HER performance is still unsatisfactory due to the low intrinsic electrical conductivity and activity of most single-phase perovskite oxides, thus impeding the practical application of perovskite oxides in overall water splitting. Lots of strategies, such as doping and defect engineering [16], surface modification [17], and morphological control [18], have been utilized to regulate the surface properties, crystal structure, and electronic structure of perovskite oxides, thus optimizing the electrocatalytic behavior. Specifically, the structure and chemical composition of perovskite oxides are highly tunable based on the specific catalytic reactions.…”

A tin‐incorporated multi‐phase perovskite nanocomposite for efficiently catalyzing oxygen evolution reaction

“…[16][17][18][19] As another significant aspect of the versatility of perovskite oxides, various approaches such as interface designing, defect engineering, strain modulation, and dimensional confinement have been developed to tailor the perovskite oxide catalysts. [20][21][22][23] Since the catalytic active sites of perovskite oxides are generally situated at the B-site transition-metal cations, and the representative activity descriptors including e g orbital occupancy and d-electron number are well correlated with the B-site cations, the physicochemical properties and catalytic activity can be readily regulated by partial replacement of B-site in the perovskite lattice with other elements. 24,25 Among them, tin has been found to be a desirable dopant in view of positive change in metal-oxygen bond energy, charge transfer ability, and electrical conductivity.…”

“…In addition, a series of perovskite derivatives with long‐range cationic ordering further expand the diversity of perovskite family, such as double perovskites (A 2 B 2 O 6 ), triple perovskites (A 3 B 3 O 9 ), quadruple perovskites (A 4 B 4 O 12 ), and Ruddlesden‐Popper perovskites (A n+1 B n O 3n+1 [n = 1, 2, and 3]) 16‐19 . As another significant aspect of the versatility of perovskite oxides, various approaches such as interface designing, defect engineering, strain modulation, and dimensional confinement have been developed to tailor the perovskite oxide catalysts 20‐23 . Since the catalytic active sites of perovskite oxides are generally situated at the B‐site transition‐metal cations, and the representative activity descriptors including e g orbital occupancy and d ‐electron number are well correlated with the B‐site cations, the physicochemical properties and catalytic activity can be readily regulated by partial replacement of B‐site in the perovskite lattice with other elements 24,25 .…”