A Photoelectrochemical Sensor Based on TiO₂ Nanotube Arrays Decorated with Nickel-Cobalt Layered Double Hydroxides for the Effective and Sensitive Detection of Chromium(VI)

Abstract

Developing stable and highly efficient photoactive materials is desirable to their extensive application in photoelectrochemical (PEC) sensors. Herein, a nickel−cobalt layered double hydroxides (NiCo-LDHs) cocatalyst-modified TiO 2 nanotube arrays (TiO 2 NTAs) photoelectrode (NiCo-LDHs/TiO 2 NTAs/ Ti) was fabricated and used to construct a PEC sensing platform for hexavalent chromium, Cr(VI), detection. The resultant NiCo-LDHs/TiO 2 NTAs/Ti showed higher photocatalytic water-splitting activity than the pristine TiO 2 NTAs/Ti, and an enhanced anodic photocurrent was realized at a potential of 0 V (vs Ag/AgCl). On the basis of changes of the photocurrent signal induced by the interaction between photogenerated electrons and Cr(VI) as an effective electron scavenger in solution, a PEC sensor for Cr(VI) detection was developed and showed a linearly decreased photocurrent with increasing Cr(VI) concentration between 0.5−20 μM, 20−400 μM, and 400−1800 μM with a 0.12 μM detection limit under the optimized test conditions. The method showed simplicity, excellent selectivity and sensitivity, a wide linearity range, and high stability. The prepared PEC sensor succeeded in the Cr(VI) detection of river water and tap water samples, and it presented good applicability.

Anderson-type polyoxometalate-based sandwich complexes bearing a new “V”-like bis-imidazole-bis-amide ligand as electrochemical sensors and catalysts for sulfide oxidation

“…To S3-S6 in the ESM) [14,34,[38][39][40][41][42][43][44][45][46][47][48][49][50]. By comparing the LODs of 1-3-CPEs for the above ions, the detection ability was found to follow the order 1-CPE > 2-CPE > 3-CPE.…”

Phase Modulation of Ti3O/R-TiO2 Nanocomposites for the Self-Powered Photoelectrochemical Sensing of Tetracycline

“…In the past decade, photoactive nanomaterials like TiO 2 , WO 3 , Co 3 O 4 , and BiVO 4 with good activity have attracted abundant attention in chemical sensing and pollutant degradation. Among them, titanium oxides have sparked considerable interest for their diverse crystalline structures and intricate optical and electrochemical properties .…”

“…3 The fundamental detection mechanism of the PEC sensor involves the alteration of photocurrent in the electrical signal induced by the interaction between the analyte and photoelectrode. 4 However, conventional PEC sensors typically rely on external energy power, limiting their potential for miniaturization, portability, and low cost toward point-of-care testing. In this regard, self-powered sensors have opened a window for on-site environmental detection without an external power supply or battery.…”

β-Bi2O3–Bi2WO6 Nanocomposite Ornated with meso-Tetraphenylporphyrin: Interfacial Electrochemistry and Photoresponsive Detection of Nanomolar Hexavalent Cr

“…TiO 2 , graphitic carbon nitride (g-C 3 N 4 ), and bismuth-based semiconductors are frequently employed for Cr 6+ detection. 19,20 Bismuth-based semiconductors, such as BiOI, Bi 2 S 3 , Bi 2 XO 6 (X = Mo, W), and others, 21 are a few examples that have drawn considerable attention in the study of photoelectrochemical analysis due to their exceptional optical and electrical qualities and also for their abundance, low toxicity, and low cost.…”

“…Since the photoelectrochemical process largely depends on the characteristics of the materials, significant effort must be put into developing electrochemical sensing materials for the detection of heavy metal ions. TiO 2 , graphitic carbon nitride (g-C 3 N 4 ), and bismuth-based semiconductors are frequently employed for Cr 6+ detection. , Bismuth-based semiconductors, such as BiOI, Bi 2 S 3 , Bi 2 XO 6 (X = Mo, W), and others, are a few examples that have drawn considerable attention in the study of photoelectrochemical analysis due to their exceptional optical and electrical qualities and also for their abundance, low toxicity, and low cost. Because of its high chemical and thermal stability, acceptable band gap energies (between 2.5 and 2.7 eV), and nontoxic properties, an aurivillius-type oxide, Bi 2 WO 6 , is regarded as a promising photocatalyst − and is now commonly used in photoelectrocatalytic solar cells, photoelectrocatalytic sensing, photoelectrocatalytic hydrogen synthesis, and water splitting .…”