Fig. 5From: The Enhanced Catalytic Activities of Asymmetric Au-Ni Nanoparticle Decorated Halloysite-Based Nanocomposite for the Degradation of Organic DyesSuccessive UV–vis absorption spectra of reduction of Congo red (a, b) and 4-nitrophenol (c, d) catalyzed by HNTs@Fe3O4@Au and HNTs@Fe3O4@Au-Ni nanocatalysts, respectively. The insets are the digital images of the degradation phenomenon reduced by the corresponding catalystsBack to article page