A highly sensitive nonenzymatic H₂O₂ sensor based on 3D N-doped porous graphene aerogel decorated with AuPd alloy nanoparticles

3D N-doped porous graphene aerogel (3D NPGA) was facilely prepared through a one-step hydrothermal reduction by mixing graphene oxide (GO) and p-phenylenediamine with ammonia solution, followed by a freeze-drying process. Then, the AuPd alloy nanoparticles were deposited on the 3D NPGA to synthesize AuPd/NPGA by reduction of HAuCl₄ and PdCl₂ using NaBH₄ as a reducing agent. NPGA composite shows a microporous with 3D structure, a large specific surface area and reveals edge plane like-sites/defects and can act as support sites for nanoparticles. The obtained AuPd/NPGA exhibits better catalytic activity towards H₂O₂ reduction compared with Pd/NPGA, Au/NPGA, and 3D NPGA composites. The improved performance of AuPd/NPGA attributed to the 3D porous structure of NPGA and the synergistic effect between Au and Pd NPs in the AuPd alloy as well as between 3D NPGA and AuPd NPs. In the 0.1 M PBS pH 7 electrolyte, the AuPd/NPGA electrode displays a linear response towards H₂O₂ reduction in the range of 1–1000 μM, high sensitivity of 12,235 μA mM⁻¹ cm⁻², low LOD 0.038 μM (S/N = 3) and quick response time (<1 s). This nonenzymatic H₂O₂ sensor was also displays satisfying selectivity, good reproducibility, and excellent long-term stability. In addition, the AuPd/NPGA electrode can also be employed for H₂O₂ detection in human serum samples. These results confirm that the AuPd/NPGA composite would be a promising catalytic material to construct sensors in different fields.