Novel pyrazole-clubbed triazole scaffolds as promising inhibitors for carbon steel corrosion in sulfuric acid and as antibacterial agents: electrochemical and computational evaluation.

Herein, two novel pyrazole-clubbed triazole scaffolds were synthesized, characterized, and evaluated as inhibitors for carbon steel dissolution in 0.5 M H2SO4 via open circuit potential (OCP), potentiodynamic polarization (PP), electrochemical impedance spectroscopy (EIS), potential of zero charge (PZC), surface characterizations, test solution analysis, and DFT studies. Maximum inhibition reached 95.3% and 93.5% for TBF and TMP, respectively, at 298 K. Based on PP, TBF and TMP function as mixed-type inhibitors, reducing current density from 324.0 µA cm- 2 to 15.30 and 21.20 µA cm- 2, whereas EIS showed an increase in charge transfer resistance from 41.90 Ω cm² to 812.6 and 633.2 Ω cm² for TBF and TMP, respectively. Inhibition peaked at 318 K and then decreased slightly at 328 K, indicating that a stable adsorbed layer had developed on the surface. Adsorption analysis revealed good agreement with the Langmuir isotherm. Following one day of immersion, Atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FT-IR), contact angle (CA), and X-ray photoelectron spectroscopy (XPS) confirmed the adsorption of the inhibitor. UV-visible spectroscopy verified chemical interactions among TBF/TMP and steel. Additionally, both compounds exhibited high antibacterial activity. Experimental findings were further supported via DFT computations and Monte Carlo (MC) simulations. The novelty of this study lies in the molecular structure of TBF and TMP, where electron-rich triazole and pyrazole rings are synergistically integrated with extended π-conjugation to enhance surface adsorption and inhibition efficiency. Moreover, the inhibitors were prepared using an eco-friendly, ultrasound-assisted method, combining high performance, cost-effectiveness, and environmental sustainability. Their outstanding thermal stability and superior inhibition efficiency in strongly acidic media underscore the innovative molecular architecture and demonstrate their potential as highly effective inhibitors under harsh conditions. Thus, the synthesized compounds effectively control corrosion, supporting future development of efficient, multifunctional, and eco-friendly inhibitors.