Regulating the Electronic Structure of Ruddlesden–Popper-Type Perovskite by Chlorine Doping for Enhanced Oxygen Evolution Activity

Abstract

Developing economical, efficient, and durable oxygen evolution catalysts is crucial for achieving sustainable energy conversion and storage. Ruddlesden–Popper-type perovskite oxides are at the forefront of oxygen evolution reaction (OER) research. However, their activity and stability are far from satisfactory. Therefore, we emphasize the paradigm shift in designing efficient perovskite-type OER catalysts through anion defect engineering. The Cl anion-doped A2BO4-type perovskite oxides, SrLaCoO4–x Cl x (SLCOCl x ), were employed as highly efficient OER catalysts, wherein Cl could tune the electronic structure of SrLaCoO4 (SLCO) to enhance the OER activity effectively. Especially, SLCOCl0.15 demonstrates significantly enhanced OER activity, and the overpotential is only 370 mV at 10 mA·cm–2, which is significantly better than that of SLCO (510 mV). As confirmed by experience results and density functional theory (DFT) calculation, due to the doping of Cl, obviously increasing the ratio of Co2+/Co3+, more abundant oxygen vacancies (O2 2–/O–) are generated, and the electrical conductivity is increased, which together promote the improvement of OER activity.

The interaction of carbon nanotubes (CNTs) with CuCoO2 nanosheets promotes structural modification and enhances their OER performance

“…Furthermore, the overpotential (at 10 mA cm −2 ) and Tafel slope of Ni@CCO/50CNT are close to or even better than those of other non-noble metal oxide catalysts (Fig. 4d and Table S3†), such as delafossite oxides, including Fe-CuCoO 2 ( η 10 = 369 mV, Tafel slope = 69 mV dec −1 ), 15 CuCoO 2 ( η 10 = 378 mV, Tafel slope = 85 mV dec −1 ), 16 and CuGaO 2 ( η 10 = 400 mV, Tafel slope = 61 mV dec −1 ); 55 other perovskite oxides, including SrLaCoO 4 ( η 10 = 370 mV, Tafel slope = 78.4 mV dec −1 ) 56 and Sr 2 CoFeO 6 ( η 10 = 360 mV, Tafel slope = 70.18 mV dec −1 ); 57 or other spinel oxides, SnCo 2 O 4 ( η 10 = 343 mV, Tafel slope = 58.93 mV dec −1 ) 58 and NiFe 2 O 4 ( η 10 = 366 mV, Tafel slope = 84.2 mV dec −1 ); 59 and other transition metal based catalysts containing CNTs, including Ni x Co 1− x @Ni x Co 1− x O/NCNT ( η 10 = 380 mV, Tafel slope = 65 mV dec −1 ) 60 and CoSnS@CNT ( η 10 = 350 mV, Tafel slope = 75 mV dec −1 ). 61…”

Chlorine-Induced Surface Reconstruction of Perovskite Oxide Boosts Oxygen Evolution Reaction Activity

“…Introducing anionic defects in the perovskite lattice through halide doping has proven to be an effective strategy for modulating oxygen vacancies, electronic structure, and surface reactivity. − Fluorine doping of SrCoO 2.85 was shown to induce a phase transition from hexagonal to tetragonal, which improved the OER activity . The change was attributed to a higher oxygen vacancy concentration and improved conductivity.…”