Structural Modification in Au-MoS2 Quantum Dot Composites for Improved Catalytic Efficiency in p-Nitrophenol Reduction

Au-MoS2 quantum dots (QDs) composites are ideal catalysts for a number of reactions, including the reduction of p-nitrophenol (PNP). However, the structural role of Au-MoS2 QDs composites in their catalytic efficiency has never been investigated. In this work, a comparative study is carried out to investigate the catalytic reactivities of a gold nanorod-molybdenum disulfide quantum dots (AuNR-MoS2 QDs) composite and a gold nanosphere-molybdenum disulfide quantum dots (AuNS-MoS2 QDs) composite. In addition, the catalytic reactivities of a gold nanorod (AuNR) and a gold nanosphere (AuNS) are also studied. The catalytic efficiency of the as-prepared composites is then investigated for the reduction of p-nitrophenol, taken as the model reaction. The kinetics of the catalytic reduction of p-nitrophenol reveal that the AuNR-MoS2 QDs composite demonstrates the highest catalytic efficiency, having a rate constant of 0.06 min-1 , compared to the AuNS-MoS2 QDs composite, AuNR, and AuNS, having a rate constant of 0.023, 0.021, and 0.008 min-1 , respectively. The possible mechanism is also discussed in the paper. Finite difference time domain (FDTD) simulation was carried out to simulate the electric field intensity of the AuNR-MoS2 QDs composite, AuNS-MoS2 QDs composite, AuNR, and AuNS. It is observed that, in general, the electric field intensity increases for the AuNR-MoS2 QDs and AuNS-MoS2 QDs composites when compared with only AuNR and AuNS. Therefore, this study emphasizes understanding the structural role of AuNR-MoS2 QDs and AuNS-MoS2 QDs composites, which is paramount in evaluating the catalytic efficiencies as demonstrated in the reduction of aromatic nitro compounds.

Automated summary

This study investigates the catalytic activities of AuNR-MoS2 QDs composite and AuNS-MoS2 QDs composite, as well as AuNR and AuNS. The results show that the AuNR-MoS2 QDs composite exhibits the highest catalytic efficiency, with a rate constant of 0.06 min-1, compared to the AuNS-MoS2 QDs composite, AuNR, and AuNS, with rate constants of 0.023, 0.021, and 0.008 min-1 respectively.