Paper strips loaded with ultrathin gold nanowires: catalytic activity and stability in the p-nitrophenol reduction

Oleylamine-coated ultrathin gold nanowires (AuNWs) were utilized to create catalytic platforms by simply dropping the colloidal synthesis product onto filter paper strips without additional treatment. These platforms were tested for their ability to catalyze the reduction of p-nitrophenol (p-NP) to p-aminophenol (p-AP) using sodium borohydride as the reducing agent. Reactions were monitored in a stirred batch recycle reactor with in situ spectrophotometric measurements, and kinetic parameters were analyzed using the Langmuir-Hinshelwood model, taking into account the residence time distribution in the experimental setup. The catalytic activity halted when the catalyst was removed, indicating a heterogeneous process with no leaching. The AuNW platforms showed reusability, successfully operating in over 20 cycles with stable activity after the initial 12 cycles. Even after harsh pretreatments, catalytic performance remained acceptable, demonstrating system robustness. The study also examined how operational conditions like p-NP and NaBH4 concentrations, as well as the number of paper strips, affected performance. The increased exposed area from using multiple strips enhanced catalytic activity. These results highlight the potential for scalable and robust industrial use of paper-supported ultrathin AuNWs without extensive washing or pretreatment. © 2025 The Royal Society of Chemistry.