Stable Fe2P2S6 Nanocrystal Catalyst for High‐Efficiency Water Electrolysis. Issue 6 (18th November 2019) - Chang, Jinfa
Abstract: A crucial step toward clean hydrogen (H2 ) energy production through water electrolysis is to develop high‐stability catalysts, which can be reliably used at high current densities for a long time. So far, platinum group metals (PGM) and their oxides, for example, Pt and iridium oxide (IrO2 ) have been well‐regarded as the criterion for hydrogen and oxygen evolution reactions (HER and OER) electrocatalysts. However, the PGM catalysts usually undergo severe performance decay during the long‐term operation. Herein, the in situ growth of iron phosphosulfate (Fe2 P2 S6 ) nanocrystals (NCs) catalysts on carbon paper synthesized by combing chemical vapor deposition with solvent‐thermal treatment is reported to show competitive performance and stability as compared to the state‐of‐the‐art PGM catalysts in a real water electrolyzer. A current density of 370 mA cm −2 is achieved at 1.8 V when using Fe2 P2 S6 NCs as bifunctional catalysts in an anion exchange membrane water electrolyzer. The Fe2 P2 S6 NCs also show much better stability than the Pt‐IrO2 catalysts at 300 mA cm −2 for a continuous 24 h test. The surface generated FeOOH on Fe2 P2 S6 is the real active site for OER. These results indicate that the Fe2 P2 S6 NCs potentially can be used to replace PGM catalysts for practical water electrolyzers. Abstract : The Fe2 P2 S6 nanocrystals (NCs) are synthesized by a facile method. A current density of 370 mA cm −2 is obtained at 1.8 V in a practical water electrolyzer using the bifunctional Fe2 P2 S6 NCs catalysts for both anode and cathode, which is comparable to the state‐of‐the‐art Pt‐IrO2 catalyst. Furthermore, the Fe2 P2 S6 NCs show much better cell stability than the Pt‐IrO2 catalysts.