Carbon quantum dots @ Pd-SnS2 nanocomposite: The role of CQDs @ Pd nanoclusters in enhancing photocatalytic reduction of aromatic nitro compounds

Mengping Liu; Ran Wang; Bing Liu; Fei Guo; Lihong Tian

doi:10.1016/j.jcis.2019.08.002

Carbon quantum dots @ Pd-SnS₂ nanocomposite: The role of CQDs @ Pd nanoclusters in enhancing photocatalytic reduction of aromatic nitro compounds

J Colloid Interface Sci. 2019 Nov 1:555:423-430. doi: 10.1016/j.jcis.2019.08.002. Epub 2019 Aug 2.

Authors

Mengping Liu¹, Ran Wang¹, Bing Liu¹, Fei Guo¹, Lihong Tian²

Affiliations

¹ Hubei Collaborative Innovation Center for Advanced Organochemical Materials, Ministry-of-Education Key Laboratory for the Synthesis and Applications of Organic Functional Molecules, Hubei University, Wuhan 430062, PR China.
² Hubei Collaborative Innovation Center for Advanced Organochemical Materials, Ministry-of-Education Key Laboratory for the Synthesis and Applications of Organic Functional Molecules, Hubei University, Wuhan 430062, PR China. Electronic address: tian7978@hubu.edu.cn.

PMID: 31398569
DOI: 10.1016/j.jcis.2019.08.002

Abstract

2D layered SnS₂ is one of the most popular semiconductor photocatalysts. However, its performance on photocatalytic reduction of aromatic nitro compounds is unsatisfactory, due to charge carrier recombination and weak adsorption of active hydrogen from the hydrolysis of NaBH₄. Herein, we have prepared CQDs @ Pd nanoclusters with Pd nanoparticles below 5 nm through an in-situ reducing Pd(Ⅱ) with CQDs containing some oxygen-containing groups at first. CQDs @ Pd-SnS₂ is achieved through a strong interaction of sulfur ions bonding on nanometric Pd surface. The composite shows a stable and efficient visible-light-driven catalytic reduction of aromatic nitro compounds in H₂O and NaBH₄. Under 40 min visible light irradiation, the conversion rate of 4-NP attains 99.7% on CQDs @ Pd-SnS₂. The first order reaction rate constant is 0.0332 min^-1, 586.5, 202.4 and 31.9 times that on SnS₂, CQDs-SnS₂ and Pd-SnS₂ in the condition of 20 mg·L^-1 4-NP and excess NaBH₄, respectively. The significant enhancement is ascribed to CQDs @ Pd promoting the charge carrier separation on SnS₂ and increasing the adsorption of active hydrogen from the hydrolysis of NaBH₄.

Keywords: Aromatic nitro compounds; CQDs @ Pd; Photocatalytic reduction; SnS(2).