Carbon-nanosheet-driven spontaneous deposition of Au nanoparticles for efficient electrochemical utilizations toward H2O2 generation and detection

Abstract

Carbon supported Au nanoparticles (NPs) with multifunctional electrocatalytic performances have captured broad interest, whereas their facile, green and efficient synthesis remains a formidable challenge. We report herein the utilization of low-cost, easy-to-prepare and efficient porous carbon (PC) with nanosheet morphology to in situ anchoring of ligand-free Au NPs via an auto-redox process-engaged strategy (APES) without involving any reductant, surfactant or organic solvent. The thermodynamically spontaneous nature for APES is ascribed to the positive △E (1.232 V) between the reduction potential of AuCl4− and the oxidation potential of PC. Note that the APES enables the formation of smaller Au NPs with high dispersion on the PC surface compared with the impregnation-reduction method, which can provide an abundance of catalytically active sites for reaction. The achieved APES-Au/PC exhibits a significant activity for 2e− oxygen reduction reaction toward H2O2 production with a concentration of 6.44 mM and H2O2 selectivity of 95% in 0.1 M KOH. The in situ formed H2O2 on APES-Au/PC electrode can be directly applied for Rhodamine B removal with a 98.7% degradation efficiency and high reusability. In addition, the APES-Au/PC electrode can be utilized to detect trace amount of H2O2 in 0.1 M PBS with a high sensitivity of 119.7 µA mM−1 cm−2, low detection limit of 1.044 µM, and wide detection range of 0.001–20 mM. This study offers a carbon nanosheet-derived APES to efficiently fabricate supported Au NPs toward versatile applications, which matches well with the principles of green and sustainable chemistry.