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

In this work, we have demonstrated that by modifying Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3-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 η 0 of ~205 and ~159 mV, and η 10 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 Co 3+ /Co 4+ 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.