One-step synthesis and electrocatalytic hydrogen evolution in self-supported tantalum carbonitrides

• Published in: Materials letters 2024-10, Vol.372, p.137025, Article 137025
• Main Authors: Sharma Mukkavilli, Raghunath, Arunkumar, B.R., Mathur, Sanjay, Kumar, Ravi
• Format: Article
• Language: English
• Subjects: Ceramics; Energy Storage and Conversion; Water splitting
• ISSN: 0167-577X; 1873-4979
• DOI: 10.1016/j.matlet.2024.137025

•Cost-effective, easily scalable synthesis of tantalum carbonitrides.•Superior HER performance (ƞ = 50 mV @ 1 mA/cm2) in a self-supported form than previously reported TaN and Ta3N5.•Low onset potential attributed to graphitic Ta-C-S interface. We report the synthesis of TaCxNy overlay on tantalum foil utilizing for the first-time melamine (C3H3N6) and thiourea (CH4N2S) as precursors to provide an ammonia-free access to carbonitride phases at 1000 °C. X-ray diffraction (XRD) and Raman analysis confirmed the formation of TaCxNy, with additional Ta2CS2 and g-C3N4 phases observed in the synthesis performed using thiourea. EDX analysis at the cross section demonstrated sulphur incorporation at the interface, indicating Ta-C-S bonds, which was supported by X-ray photoelectron spectroscopy (XPS). The resulting materials were evaluated as self-supported electrodes for electrocatalytic hydrogen evolution reaction (HER). A low overpotential (50 mV at 1 mA/cm2) and stability of 6 h (at −15 mA/ cm2) was delivered in the catalyst synthesized from thiourea attributed to graphitic Ta-C-S moieties at the interface.