Construction of polydopamine (PDA) functionalized CeO2/In2S3 heterojunction for photoelectrochemical monitoring of glucose and hexavalent chromium

In this paper, PDA n /CeO 2 /In 2 S 3 -X (X = m(CeO 2 )/m(CeO 2 +In 2 S 3 ), n = m(PDA)/ m(catalyst)) heterojunction was successfully fabricated by three steps to detect glucose and hexavalent chromium (Cr(VI)). CeO 2 was initially synthesized by calcination , followed by a hydrothermal method to make In 2 S 3 compounded with CeO 2 . Specifically, by optimizing the ratio of CeO 2 and In 2 S 3 , CeO 2 /In 2 S 3 -15 % showed the best photoelectric responses and sensing performances. In order to further improve the performance, polydopamine (PDA) was modified on the surface of CeO 2 /In 2 S 3 -15 % (PDA n /CeO 2 /In 2 S 3 -15 %). Besides, the results from optical characterizations and performance testings showed that PDA 0.1 /CeO 2 /In 2 S 3 -15 % exhibits the best absorption capacity and photocurrent responses. Interestingly, PDA 0.1 /CeO 2 /In 2 S 3 -15 % was applied to detect Cr(VI) and glucose in an effective fashion. The PEC glucose sensor based on PDA 0.1 /CeO 2 /In 2 S 3 -15 % showed an acceptable detection range between 0.5 μM and 27 mM with good sensitivity (575.20 µA·mM −1 ·cm −2 ) and low detection limit (0.076 μM). Meanwhile, for Cr(VI) sensing, it has a wide linear range of 0.5–240 µM with a high sensitivity of 1053.60 µA·mM −1 ·cm −2 , and the low detection limit is 0.098 µM. Furthermore, it could be also employed in real samples (human blood serum or sewage). Thus, the PEC sensor based on PDA/CeO 2 /In 2 S 3 has potential applications in glucose and Cr(VI) detection.