Heteroanionic materials leverage multiple anion species in their sublattices to achieve even greater structural diversity and adjustable electronic structure properties compared to more ubiquitously-studied homoanionic materials, such as the broad class of oxides. In addition to providing immense opportunities for material design, these materials may also exhibit enhanced functionality for electrocatalytic reactions. Particularly, perovskite oxynitrides offer enhanced geometric and electronic flexibility via incorporation of N anions and provide greater opportunity for tuning metal-anion covalency compared to their perovskite oxide counterparts. However, direct synthesis of such materials is extremely difficult. In fact, only early transition metal-based perovskite oxynitride has been successfully prepared, because late transition metals have reduced affinity for coordinating with nitrogen or maintaining a high valence states during reductive ammonolysis processes.<br/>Herein, we present an approach to synthesize a perovskite oxynitride lattice using more stable early transition metals and incorporate late transition metal dopants (i.e. iridium) in the perovskite oxynitride lattice (Figure 1) to serve as catalytic active sites. Through a series of characterization, including x-ray absorption spectroscopy and atomic resolution electron microscopy, we demonstrate successful synthesis of this novel material and discover a unique Ir-N/O coordination structure, which we identify as a highly efficient active site for the hydrogen evolution reaction. The mass activity (normalized to precious metal loading) surpasses that of commercial Pt/C while demonstrating stability for more than 3000 CVs, highlighting perovskite oxynitrides as a promising research avenue for electrocatalyst design.

Incorporating iridium atoms into strontium tungsten oxynitride perovskite as an efficient electrocatalyst towards hydrogen evolution in acid electrolytes

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.