Enabling efficient hydrogen-evolution reaction over perovskite oxide electrocatalysts through phosphorus promotion

Abstract In this work, we have demonstrated that by modifying Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) via phosphorous (P) incorporation, the hydrogen evolution reaction (HER) activity was boosted. Such P incorporation was realized through the lattice doping via an in situ method, or bulk/surface co-modification via an ex situ approach. Under optimal conditions, the derived P-doped and bulk/surface-modified BSCF exhibited η0 of ~205 and ~159 mV, and η10 of ~333 and ~309 mV in 1.0 M KOH, respectively. Such attractive performance resulted from multiple aspects, including the improved electrochemical active surface area, accelerated charge transfer kinetics, increased high-oxidation state of the Co cation within the Co3+/Co4+ redox couple, and enlarged amount of lattice oxygen species. Moreover, the presence of amorphous regions and structure distortion of P-modified BSCF from the ex situ method greatly facilitated the HER.