Hui Zheng

Bio: Hui Zheng is an academic researcher from Jilin Normal University. The author has contributed to research in topics: Methyl orange & Surface plasmon resonance. The author has an hindex of 4, co-authored 5 publications receiving 54 citations.

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.

Recyclable Magnetic MIP-Based SERS Sensors for Selective,Sensitive, and Reliable Detection of Paclobutrazol Residues in Complex Environments

Abstract: In this work, a molecularly imprinted polymers (MIPs)-based SERS sensor for selective, sensitive, quantitative and recyclable detection of paclobutrazol residue in complex environments has been pro...

A Novel Au@Cu2O-Ag Ternary Nanocomposite with Highly Efficient Catalytic Performance: Towards Rapid Reduction of Methyl Orange Under Dark Condition

Abstract: Au@Cu2O core-shell nanocomposites (NCs) were synthesized by reducing copper nitrate on Au colloids with hydrazine. The thickness of the Cu2O shells could be varied by adjusting the molar ratios of Au: Cu. The results showed that the thickness of Cu2O shells played a crucial role in the catalytic activity of Au@Cu2O NCs under dark condition. The Au@Cu2O-Ag ternary NCs were further prepared by a simple galvanic replacement reaction method. Moreover, the surface features were revealed by TEM, XRD, XPS, and UV–Vis techniques. Compared with Au@Cu2O NCs, the ternary Au@Cu2O-Ag NCs had an excellent catalytic performance. The degradation of methyl orange (MO) catalyzed by Au@Cu2O-Ag NCs was achieved within 4 min. The mechanism study proved that the synergistic effects of Au@Cu2O-Ag NCs and sodium borohydride facilitated the degradation of MO. Hence, the designed Au@Cu2O-Ag NCs with high catalytic efficiency and good stability are expected to be the ideal environmental nanocatalysts for the degradation of dye pollutants in wastewater.

Towards practical and sustainable SERS: a review of recent developments in the construction of multifunctional enhancing substrates

Abstract: Surface-enhanced Raman spectroscopy (SERS) is a powerful analytical technique, which allows quantitative detection of chemical species with molecular specificity and single-molecule sensitivity. These useful properties can be further combined with portable Raman spectrometers which allow SERS to be potentially employed at the point-of-care. As a result, SERS has found a wide range of potential applications in both real-life chemical analysis and fundamental mechanistic studies. Despite these advantages, true applications of SERS have been limited due to its high cost, which arises mainly from the fact that SERS relies on expensive single-use Ag/Au enhancing substrates suitable only for the analysis of pure samples. A viable approach to address this issue is to develop multifunctional SERS substrates, which in addition to providing Raman signal enhancement, is armed with other practical functionalities that simplifies the analysis and/or allows the substrate to be regenerated for repeated use. This review gives an account of the recent progress in the fabrication of multi-functional SERS substrates, namely flexible, separation-enhancement-in-one, calibration-enhancement-in-one and regeneration-enhancement-in-one substrates. Specific focus is placed on summarizing and discussing the most widely used strategies to incorporate each type of functionality and their respective advantages and drawbacks. Finally, we present our perspectives on the future challenges and potential opportunities in the development of smart multifunctional SERS sensors for achieving sustainable and wide-spread application of SERS.

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.

Au@TiO2 Core-Shell Composites for the Photocatalytic Reduction of CO2.

Abstract: Au/TiO2 catalysts in different geometrical arrangements were designed to explore the role of morphology and structural properties for the photocatalytic reduction of CO2 with H2 O in the gas-phase. The most active sample was a Au@TiO2 core-shell catalyst with additional Au nanoparticles (NPs) deposited on the outer surface of the TiO2 shell. CH4 and CO are the primary carbon-containing products. Large amounts of H2 are additionally formed by photocatalytic H2 O splitting. Shell thickness plays a critical role. The highest yields were observed with the thickest layer of TiO2 , stressing the importance of the semiconductor for the reaction. Commercial TiO2 with and without Au NPs was less active in the production of CH4 and CO. The enhanced activation of CO2 on the core-shell system is concluded to result from electronic interaction between the gold core, the titania shell, and the Au NPs on the outer surface. The improved exposure of Au-TiO2 interface contributes to the beneficial effect.

Highly Efficient Silver Catalyst Supported by a Spherical Covalent Organic Framework for the Continuous Reduction of 4-Nitrophenol.

Abstract: Developing new materials and novel technologies for the highly efficient treatment of toxic organic pollutants is highly desirable. Chemical reduction based on heterogeneous substrate/noble metal catalysts and the reducing agent NaBH4 has become an effective method in recent years. Here, a spherical covalent organic framework (SCOF) was designed to provide basic sites for Ag ions, by which small Ag NPs were immobilized on the SCOF to form Ag NPs@SCOF microspheres. The prepared microspheres exhibited a high catalytic reduction ability toward 4-nitrophenol (4-NP). An optimized permeation flux of 2000 L m(-2) h(-1) (LMH) and a more than 99% 4-NP reduction efficiency were obtained with flow-through experiments, which are far better than the reported results (below 200 LMH). Moreover, the microspheres could maintain stable catalytic performance under a continuous flow-through process. Our work provides an efficient material and technology that can be applied to easily treat toxic organic pollutants.