Bifunctional technology involving RuO2-IrO2/Ti electrode decorated with reduced graphene oxide aerogel with Pd nanoparticles: Electrochemical oxidative decomposition and detection of p-nitrophenol

[Display omitted] •Electrochemical detection and oxidative degradation of p-nitrophenol were studied.•A reduced-graphene-oxide aerogel with Pd nanoparticles (rGO-A/Pd-NP) was prepared.•An rGO-A/Pd-NP sensor and a RuO2–IrO2–rGO-A/Pd-NP electrode were fabricated.•The mechanism of p-nitrophenol decomposition was clarified based on •OH generation.•The practical viability of the sensor was demonstrated using real water samples. In this study, a nanocomposite containing a reduced-graphene-oxide aerogel decorated with Pd nanoparticles (rGO-A/Pd-NP), an rGO-A/Pd-NP sensor, and a RuO2–IrO2–rGO-A/Pd-NP composite electrode were prepared to electrochemically detect p-nitrophenol and elucidate the mechanism underlying electrochemical oxidative p-nitrophenol degradation. The composite electrode exhibited an outstanding electrolytic p-nitrophenol removal efficiency (96.1%) in addition to a noteworthy chemical oxygen demand and total-organic-carbon removal efficiency (88.4% and 70.2%, respectively). Optimal p-nitrophenol decomposition was achieved using an initial p-nitrophenol concentration of 50 mg mL−1, a pH of 3, and a current density of 40 mA cm−2. p-Nitrophenol was found to decompose via electrochemical oxidation by hydroxyl radicals generated on the anode surface, with the reaction following pseudo-first-order kinetics. The rGO-A/Pd-NP sensor showed excellent reduction-based p-nitrophenol sensing performance (linear range, 0.1–20 mg L−1 [R2 = 0.9919]; detection limit, 0.052 mg L−1). Overall, an organic contaminant in natural water was rapidly detected using a sensor electrodeposited with the rGO-A/Pd-NP nanocomposite, and the electrolytic p-nitrophenol removal efficiency was improved by incorporating functional rGO-A/Pd-NP particles into a Ti/RuO2–IrO2 electrode. The convergent technology reported herein for detecting and removing harmful substances will open a new avenue for nanocomposite catalyst applications in electroanalytical chemistry.