Plasma-Assisted Surface Nitridation of Proton Intercalatable WO<sub>3</sub> for Efficient Electrocatalytic Ammonia Synthesis
Z. Y. Zhang, Christopher Kondratowicz, Jacob Smith, Pavel Kucheryavy, Junjie Ouyang, Yijie Xu, Elizabeth Desmet, Sophia Kurdziel, Enhui Tang, Micheal Adeleke, Aditya Lele, John Mark P. Martirez, Miaofang Chi, Yiguang Ju, Huixin He
Abstract
Electrocatalytic nitrogen reduction (eNRR) offers a green pathway for the production of NH 3 from N 2 and H 2 O under ambient conditions. Transition metal oxynitrides (TMO x N y ) are among the most promising catalysts but face challenges in achieving a high yield and faradaic efficiency (FE). This work develops a hybrid WO x N y /WO 3 catalyst with a unique heterogeneous interfacial complexion (HIC) structure. This design enables in situ generation and delivery of highly active hydrogen atoms (H*) in acidic electrolytes, promoting nitrogen hydrogenation and the formation of nitrogen vacancies (Nv) on the WO x N y surface. This significantly enhances the selectivity of eNRR for NH 3 synthesis while suppressing the hydrogen evolution reaction (HER). A simple two-step fabrication process─microwave hydrothermal growth followed by plasma-assisted surface nitridation─was developed to fabricate the designed catalyst electrode, achieving an NH 3 yield of 3.2 × 10 –10 mol·cm –2 ·s –1 with 40.1% FE, outperforming most TMN/TMO x N y electrocatalysts. Multiple control experiments confirm that the eNRR follows an HIC-enhanced Mars–van Krevelen (MvK) mechanism.