Construction of micro-tubular proton-conducting ceramic electrochemical reactor (MT-PCER) for ammonia production at atmospheric pressure

Micro-tubular ceramic electrochemical reactors have attracted significant interest due to their high packing density, large electrode specific surface area, and long triple phase boundaries (TPBs). In this work, a micro-tubular proton-conducting ceramic electrochemical reactor (MT-PCER) with a unique microstructure is facilely constructed for ammonia synthesis at atmospheric pressure. BaCe0.7Zr0.1Y0.2O3-δ (BCZY as the electrolyte)/Ni–BaCe0.7Zr0.1Y0.2O3-δ (Ni-BCZY as the catalytic cathode) dual-layer hollow fibers with open finger-like pores on the inner surface are first fabricated using a modified co-spinning/co-sintering process to form a basic MT-PCER. Fe-based catalyst was then coated into these open finger-like pores in Ni-BCZY layer as an additional catalytic cathode of the MT-PCER. The unique open finger-like pores structure of the basic MT-PCER decreases the mass transfer resistance and also provides space for loading additional catalysts, contributing towards the higher catalytic performance of the MT-PCER. However, the Faradaic efficiency for ammonia formation remained low, indicating that the cathode catalyst required further improvement. This fabrication technique provides a flexible method to adjust the cathode catalysts to optimize the catalytic performance of the MT-PCERs.