Lattice site-dependent metal leaching in perovskites toward a honeycomb-like water oxidation catalyst.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 34890227.
- Also identified by DOI 10.1126/sciadv.abk1788 and PMC identifier 8664262.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Metal leaching during water oxidation has been typically observed in conjunction with surface reconstruction on perovskite oxide catalysts, but the role of metal leaching at each geometric site has not been distinguished. Here, we manipulate the occurrence and process of surface reconstruction in two model ABO<sub>3</sub> perovskites, i.e., SrSc<sub>0.5</sub>Ir<sub>0.5</sub>O<sub>3</sub> and SrCo<sub>0.5</sub>Ir<sub>0.5</sub>O<sub>3</sub>, which allow us to evaluate the structure and activity evolution step by step. The occurrence and order of leaching of Sr (A-site) and Sc/Co (B-site) were controlled by tailoring the thermodynamic stability of B-site. Sr leaching from A-site mainly generates more electrochemical surface area for the reaction, and additional leaching of Sc/Co from B-site triggers the formation of a honeycomb-like IrO<i><sub>x</sub></i>H<i><sub>y</sub></i> phase with a notable increase in intrinsic activity. A thorough surface reconstruction with dual-site metal leaching induces an activity improvement by approximately two orders of magnitude, which makes the reconstructed SrCo<sub>0.5</sub>Ir<sub>0.5</sub>O<sub>3</sub> among the best for water oxidation in acid.