Meso-tetra(4-sulfonatophenyl)porphyrin silver/Ag nanoparticles/graphene-phase C3N4 with a sandwich-like structure and double-faced active centers via two-step room-temperature photocatalytic synthesis for ractopamine detection

Xuehua Weng; Huiling Ye; Wenqiang Xie; Meihui Ying; Haibo Pan; Min Du

doi:10.1039/d1na00130b

Meso-tetra(4-sulfonatophenyl)porphyrin silver/Ag nanoparticles/graphene-phase C₃N₄ with a sandwich-like structure and double-faced active centers via two-step room-temperature photocatalytic synthesis for ractopamine detection

Nanoscale Adv. 2021 May 18;3(13):3900-3908. doi: 10.1039/d1na00130b. eCollection 2021 Jun 30.

Authors

Xuehua Weng^{1

2}, Huiling Ye^{1

2}, Wenqiang Xie^{1

2}, Meihui Ying^{1

2}, Haibo Pan^{1

2

3}, Min Du³

Affiliations

¹ National & Local Joint Biomedical Engineering Research Center on Photodynamics Technology Fuzhou Fujian 350108 P. R. China.
² College of Chemistry, Fuzhou University Qishan Campus Fuzhou Fujian 350108 China [email protected].
³ Fujian Key Lab of Medical Instrument and Pharmaceutical Technology, Fuzhou University Fuzhou Fujian 350108 China.

Abstract

Photochemical synthesis under visible light irradiation is a novel approach in the field of green chemistry, and composites with abundant active centers for electrochemical detection are highly attractive. Herein, a meso-tetra(4-sulfonatophenyl)porphyrin silver/Ag nanoparticles/graphene phase C₃N₄ nanosheets (Ag₂TPPS₄/AgNPs/ng-C₃N₄) material with a sandwich-like structure was synthesized using a two-step photocatalytic reaction at room temperature (25 °C). In the first visible light irradiation step and in the presence of a hole capture agent, Ag⁺ ions were photocatalytically reduced onto the surface of ng-C₃N₄ that was used as a photocatalyst. Then, the protons (H⁺) in the core of H₂TPPS₄ were substituted in situ by photo-oxidized Ag⁺ during the second visible light irradiation step and in the presence of an electron capture agent. The electrochemical response of Ag₂TPPS₄ and ng-C₃N₄ to ractopamine (RAC) results in the unique double-faced active centers of Ag₂TPPS₄/AgNPs/ng-C₃N₄, and the cores (AgNPs) are beneficial as bridges for the connection between Ag₂TPPS₄ and ng-C₃N₄ and for high-efficiency electron transfer. Hence, as-synthesized Ag₂TPPS₄/AgNPs/ng-C₃N₄ exhibits high sensitivity (a low detection limit of 5.1 × 10^-8 M, S/N = 3.0), a wide linear range (1 × 10^-7 to 1.2 × 10^-5 M), and long-term stability. Based on the experimental verification of the electrochemical dynamics and electrostatic attraction at the interface between the dual-active-center surface and RAC, the electrochemical mechanism has been clarified. Specifically, in the multi-cycle oxidation of RAC, the blue shift of specific UV-vis peaks also confirms the electrocatalytic oxidation of the two terminal hydroxyl groups of RAC. In brief, Ag₂TPPS₄/AgNPs/ng-C₃N₄ with a sandwich-like structure and double-faced active centers enhances the detection sensitivity and electrocatalytic efficiency towards RAC.