Self-sustainable and recyclable ternary Au@Cu2O–Ag nanocomposites: application in ultrasensitive SERS detection and highly efficient photocatalysis of organic dyes under visible light

Abstract

Ternary noble metal–semiconductor nanocomposites (NCs) with core–shell–satellite nanostructures have received widespread attention due to their outstanding performance in detecting pollutants through surface-enhanced Raman scattering (SERS) and photodegradation of organic pollutants. In this work, ternary Au@Cu2O–Ag NCs were designed and prepared by a galvanic replacement method. The effect of different amounts of Ag nanocrystals adsorbed on the surfaces of Au@Cu2O on the SERS activity was investigated based on the SERS detection of 4-mercaptobenzoic acid (4-MBA) reporter molecules. Based on electromagnetic field simulations and photoluminescence (PL) results, a possible SERS enhancement mechanism was proposed and discussed. Moreover, Au@Cu2O–Ag NCs served as SERS substrates, and highly sensitive SERS detection of malachite green (MG) with a detection limit as low as 10−9 M was achieved. In addition, Au@Cu2O–Ag NCs were recycled due to their superior self-cleaning ability and could catalyze the degradation of MG driven by visible light. This work demonstrates a wide range of possibilities for the integration of recyclable SERS detection and photodegradation of organic dyes and promotes the development of green testing techniques.

Photoluminescence properties of cuprous phosphide prepared through phosphating copper with a native oxide layer

“…The peak can be tted into three subpeaks, centered at 631.4 nm, 734.2 nm and 796.3 nm, respectively. We speculate that the peak at 631.4 nm is from the band-edge uorescence emission of Cu 2 O, the peak at 734.2 nm from Cu 3 P, and the peak at 796.3 nm from the impurity level emission of Cu 3 P. 12,35 In addition, the PL intensity of Cu 3 P is weaker than that of Cu 2 O. Aer annealing, the peak of Cu 2 O blueshis to 606.6 nm, and the peak of Cu 3 P redshis to 749.4 nm, and the peak at 796.3 nm disappears. The shis of the peak should be related to the improvement of the crystal quality and grain boundary.…”

Chemical Vapor Deposition and Thermal Oxidation of Cuprous Phosphide Nanofilm

“…Cuprous phosphide is a direct band gap semiconductor with a band gap of ca. 1.5 eV The photon energy of the broad-band emission is higher than the band gap of Cu3P Therefore, the broad-band emission is not due to Cu3P, but copper oxides [18,31,32]. So where do these copper oxides come from?…”

Laser Fabricated Cu2O‐CuO/Ag Nanocomposite Films for SERS Application**

“…As SERS based on molecular vibrations and/or rotations can offer intrinsic fingerprint information about specific molecules, it has been identified as a promising spectral analytical technique [2] . In addition to its rapidity and specificity, SERS has the advantages of non‐destruction of analytes, high detection accuracy and trace‐level sensitivity, and in situ identification, [3] resulting in a wide range of applications in the fields of environmental monitoring, [4] drug detection, [5] explosives analyses, [6] as well as healthcare inspection [7] . The high sensitivity of SERS detection comes from electromagnetic (EM) and chemical enhancement effects [8] of used substrate.…”