The sensitive and selective detection of toxic Cr (VI) depends on the development of high-performance photoelectrochemical sensing materials. Herein, two supramolecular architectures of CuIP4Mo62-based phosphomolybdates, with formula of (H2bib) 3PbCuIP4Mo6O312H15·10H2O (1), CuI (bib) 4Na2 (H2O) 7CuIP4Mo6O312H17·26H2O (2) (bib = 4, 4'-bis (imidazolyl) bipheny), were synthesized as photoelectrochemical sensors for determining Cr (VI) ion. Compound 1 consisted of one-dimensional Pb2+-bridged fully reduced CuIP4Mo62 clusters and protonated H2bib2+ cations. Compound 2 was composed of Na+-capped CuIP4Mo62 clusters and CuI (bib) + chains. Both compounds 1 and 2 displayed excellent electrochemical redox properties, broad spectral absorption capabilities, and rapid photoelectrochemical response. Using as photoelectrochemical sensors, compound 1 showed a high sensitivity of 255. 41 μA·μM-1 and an extremely low detection limit of 0. 54 nM (0. 056 ppb) toward Cr (VI) detection, and compound 2 presented a sensitivity of 62. 53 μA·μM-1 and detection limit of 3. 64 nM (0. 38 ppb). Structure-function relationship analysis showed that the one-dimensional framework of CuIP4Mo62 clusters effectively promotes the separation and transport of photogenerated charge carriers. Compound 1 also exhibited high anti-interference capability and stability in the photoelectrochemical detection process. This work provides some insights for designing advanced polyoxometalate-based sensor materials for highly efficient monitoring of environmental pollutants.
Yin et al. (Thu,) studied this question.