Tailoring hybrid CrCoSb-B nano-needles via Ar plasma: A path to sustainable water splitting and urea oxidation

Abstract

Green hydrogen (H2) is a promising fossil fuel alternative, valued for its high energy content and negligible greenhouse gas emissions. The growing demand for sustainable energy solutions necessitates cost-effective, highly efficient, and durable electrocatalysts to enable large-scale H2 production. In our study an innovative approach by introducing a novel tri-metallic hybrid electrocatalyst, CrCoSb-B was surface treated with vacuum Ar plasma for the 1st time. This approach creates a highly efficient charge transfer within the electrocatalysts structure. Boron (B) atoms are added to expedite the water-splitting process by aiding electron transfer to the metal surfaces (Cr, Co, and Sb). On the other hand, Ar plasma treatment increases the number of active catalytic sites on the electrode surface, improving water-splitting efficiency. As a result, the CrCoSb-B electrode, subjected to 2 min Ar plasma treatment, exhibits significantly reduced overpotentials of 265 mV for hydrogen evolution reaction (HER) and 453 mV for oxygen evolution reaction (OER) at a high current density of 1000 mA/cm2 in a 1.0 M KOH electrolyte with the low Tafel values for HER and OER are 68 and 97 mV/dec, respectively. In bi-functional operation, the electrocatalyst achieves a low voltage of 2.01 V at 1000 mA/cm2 and demonstrates enhanced performance in the urea oxidation reaction (UOR) with a voltage of 1.81 V at 1000 mA/cm2. Furthermore, it maintains stability over a 24 hrs duration and nearly 100% Faradic efficiency in both H2 and O2 production. This research reveals a promising path for developing effective electrocatalysts, leveraging interfacial interactions and vacancies to enhance their performance in green hydrogen production.