Ag2S QDs integration with MnO2 nanosheets for the sensitive detection of Cr (VI) via the redox reaction induced photoelectrochemical variation

Lili Zhao; Haoyu Chen; Ying Tang; Peipei Li; Xiaohua Zhu; Jingyi Liu; Meiling Liu; Youyu Zhang; Shouzhuo Yao

doi:10.1016/j.aca.2023.341471

Ag₂S QDs integration with MnO₂ nanosheets for the sensitive detection of Cr (VI) via the redox reaction induced photoelectrochemical variation

Anal Chim Acta. 2023 Aug 22:1270:341471. doi: 10.1016/j.aca.2023.341471. Epub 2023 Jun 2.

Authors

Lili Zhao¹, Haoyu Chen¹, Ying Tang¹, Peipei Li¹, Xiaohua Zhu¹, Jingyi Liu², Meiling Liu³, Youyu Zhang¹, Shouzhuo Yao¹

Affiliations

¹ Key Laboratory of Chemical Biology & Traditional Chinese Medicine Research (Ministry of Education, China), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha, 410081, PR China.
² State Environmental Protection Key Laboratory of Monitoring for Heavy Metal Pollutants, PR China.
³ Key Laboratory of Chemical Biology & Traditional Chinese Medicine Research (Ministry of Education, China), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha, 410081, PR China. Electronic address: liumeilingww@126.com.

PMID: 37311614
DOI: 10.1016/j.aca.2023.341471

Abstract

The heavy metal Cr (VI) will remain, accumulate, and migrate after entering the environment or ecosystem, causing serious harm to the environment. Here, a photoelectrochemical sensor was developed for Cr (VI), utilizing the Ag₂S quantum dots (QDs) and MnO₂ nanosheets as photoactive components. By introducing Ag₂S QDs with a narrow gap, a staggered energy level match is created which effectively prevents the carrier recombination in MnO₂ nanosheets, resulting in an enhanced photocurrent response. In the presence of the electron donor, l-ascorbic acid (AA), the photocurrent of the Ag₂S QDs and MnO₂ nanosheets modified photoelectrode is further enhanced. As AA has the ability to convert Cr (VI) to Cr (Ⅲ), the photocurrent may decline due to the decrease in the electron donors when Cr (VI) is added. This phenomenon can be utilized for the sensitive detection of Cr (VI) over a wider linear range (100 pM-30 μM) with a lower detection limit of 6.46 pM (S/N = 3). This work using the strategy that the targets induced the variations of the electron donor shows the advantages of good sensitivity and nice selectivity. The sensor holds many advantages such as simple fabrication process, economical material expense, and consistent photocurrent signals. It also holds significant potential for environmental monitoring and serves as a practical photoelectric sensing approach for detecting Cr (VI).

Keywords: Ag(2)S quantum Dots (QDs); Cr (VI); MnO(2) nanosheets; Photoelectrochemical sensing; l-ascorbic acid.