ABSTRACT
Single atom catalysts (SACs) with the maximized metal atom efficiency have sparked great attention. However, it is challenging to obtain SACs with high metal loading, high catalytic activity, and good stability. Herein, we demonstrate a new strategy to develop a highly active and stable Ag single atom in carbon nitride (Ag-N2 C2 /CN) catalyst with a unique coordination. The Ag atomic dispersion and Ag-N2 C2 configuration have been identified by aberration-correction high-angle-annular-dark-field scanning transmission electron microscopy (AC-HAADF-STEM) and extended X-ray absorption. Experiments and DFT calculations further verify that Ag-N2 C2 can reduce the H2 evolution barrier, expand the light absorption range, and improve the charge transfer of CN. As a result, the Ag-N2 C2 /CN catalyst exhibits much better H2 evolution activity than the N-coordinated Ag single atom in CN (Ag-N4 /CN), and is even superior to the Pt nanoparticle-loaded CN (PtNP /CN). This work provides a new idea for the design and synthesis of SACs with novel configurations and excellent catalytic activity and durability.
ABSTRACT
In this study, new clindamycin (CLIN) artificial antigens were prepared and used to produce broad-specificity monoclonal antibodies. Based on the as-produced mAbs, a heterologous ELISA was developed to detect CLIN and lincomycin (LIN) residues in edible animal tissues. The IC50 values of the developed assay were 0.3ng/mL (CLIN) and 1.2ng/mL (LIN) in buffer, respectively. The detection limits were estimated to be 1.8µg/kg (CLIN) and 6.8µg/kg (LIN) in bovine, chicken, porcine and fish muscles. In the spike and recovery tests, the mean recovery rate ranged from 76% to 112% at different spiked levels, and the intra-/inter-assay coefficients of variation were in the range of 7.1% to 13.2%. This method was verified using LC-MS/MS with a correlation coefficient >0.97. The developed ELISA is therefore well suited for simultaneous determination of CLIN and LIN residues in bovine, chicken, porcine and fish muscles.
