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

• Auto-redox process-engaged strategy (APES) is developed to anchor Au NPs on PC. • The driving force is the positive △ E between reduction potentials of AuCl 4 − and PC . • APES enables the formation of smaller Au NPs with high dispersion on PC surface. • APES-Au/PC is a multiple electrocatalyst for efficient H 2 O 2 -related applications. 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 AuCl 4 − 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 H 2 O 2 production with a concentration of 6.44 mM and H 2 O 2 selectivity of 95% in 0.1 M KOH. The in situ formed H 2 O 2 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 H 2 O 2 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.