Enhanced activity for electrocatalytic H2 production through cooperative Pr and Bi co-doping of CeO2 in solid oxide electrolysis cells
Tiantian Wu, Tejs Vegge, Heine Anton Hansen
Abstract
CeO2-based catalysts as cathodes in solid oxide electrolysis cells (SOECs) have great potential for improving the storage of renewable electricity in the form of H2 via the water-splitting reaction (WSR). A key challenge to promote the WSR on CeO2 is facilitating the decomposition of stable surface hydroxides to form H2. Here, we use density functional theory to investigate the effect of Bi- and Pr- doping for the WSR on CeO2(1 1 1). We find that dopants influence the stability of hydridic H, which can be formed during the decomposition of hydroxyl to H2. By stabilizing hydridic H on Bi during the H2 formation step, Bi and Pr co-doped into ceria lower the barrier to H2 formation, enhancing the rate of WSR by 2–4 orders of magnitude compared to individually Pr-, Bi- or Gd-doped CeO2. We suggest co-doping as an effective strategy for improving the WSR in SOECs.