Preferential Cation Vacancies in Perovskite Hydroxide for the Oxygen Evolution Reaction

Abstract

The oxygen evolution reaction (OER) is an ideal model to study the relationship between the activity and the surface properties of catalysts. Defect engineering has been extensively developed to tune the electrocatalytic activity for OER. Compared to the anion vacancies in metal oxides, cation vacancies are more challenging to selectively generate, and the insight into the structure and activity of cation vacancies-rich catalysts are lacked. Herein, using SnCoFe perovskite hydroxide as a precursor, abundant Sn vacancies on the surface were preferentially produced by Ar plasma. Sn vacancies could be preferentially produced as confirmed by the X-ray absorption spectra, probably owing to the lower lattice energy and weaker chemical bonds of Sn(OH) . The Sn vacancies promoted the exposure of active CoFe sites, resulting in an amorphous surface layer, modulated the conductivity, and thus enhanced the OER performance.

A Plasma‐Triggered O−S Bond and P−N Junction Near the Surface of a SnS2 Nanosheet Array to Enable Efficient Solar Water Oxidation

“…Figure c shows the S peaks shift negatively after Ar plasma treatment, suggesting increased electron density around S, which is due to the fact that the Sn 2+ brings the weak binding energy with S. It is noted that a new peak at 168.9 eV related with the O−S bond is observed for SnS 2 ‐P . To further characterize the formed O−S bond, X‐ray absorption spectroscopy (XAS) was used to survey the Sn L 3 and S K absorption edges . Figure d shows the Sn L 3 ‐edge X‐ray absorption near‐edge structure (XANES) curves of SnS 2 and SnS 2 ‐P.…”

Identification of Key Reversible Intermediates in Self‐Reconstructed Nickel‐Based Hybrid Electrocatalysts for Oxygen Evolution

“…The decreased Tafel slope of 46 mV dec −1 suggests the considerable structure modification in NiNPS with optimized oxygenic intermediate adsorption energy. It is worth to note that the electrocatalytic properties of the as‐obtained NiNPS towards water oxidation are much better than that of most previous reports . These results are further evidenced by the decreased charge transfer resistance ( R ct ) from about 13.11 to 1.48 Ω, which means that NiNPS possesses a superior electron transfer ability and lower energy barrier in comparison with the pristine NiN (Figure d).…”

A Plasma‐Triggered O−S Bond and P−N Junction Near the Surface of a SnS2 Nanosheet Array to Enable Efficient Solar Water Oxidation

“…[28] Figure 2d shows the Sn L 3 -edge X-ray absorption near-edge structure (XANES) curves of SnS 2 and SnS 2 -P.Asobserved in the spectra in Figure 2d,there are peaks in L 3 edge dotted line observed around 3953 eV and 3965 eV for SnO and SnO 2 , respectively.T he dotted line intensity is only affected by the final unoccupied states above the Fermi level where the dotted lines at the L 3 edge originate from the initial state of 2p 3/2 and 2p 1/2 ,a nd correspond to the different final states of d 5/2 and d 3/2 ,respectively.Moreover,there are two weak peaks (3920-3950 eV) in the spectra of SnO and SnO 2 which were assigned to the 2p 3/2 -5s 1/2 transition. [28] Figure 2d shows the Sn L 3 -edge X-ray absorption near-edge structure (XANES) curves of SnS 2 and SnS 2 -P.Asobserved in the spectra in Figure 2d,there are peaks in L 3 edge dotted line observed around 3953 eV and 3965 eV for SnO and SnO 2 , respectively.T he dotted line intensity is only affected by the final unoccupied states above the Fermi level where the dotted lines at the L 3 edge originate from the initial state of 2p 3/2 and 2p 1/2 ,a nd correspond to the different final states of d 5/2 and d 3/2 ,respectively.Moreover,there are two weak peaks (3920-3950 eV) in the spectra of SnO and SnO 2 which were assigned to the 2p 3/2 -5s 1/2 transition.…”