Energy band-adjusted BiPO4/BiOClxBr1-x photoelectrochemical sensor for enhancing 4-CP detection

Abstract

BiPO4 nanoparticles were loaded into BiOClxBr1-x with hierarchical flower-like structures by hydrothermal method, and an energy band-adjusted BiPO4/BiOClxBr1-x heterojunction with high photoelectrochemical properties was synthesized. Comparing BiPO4 and BiOClxBr1-x to BiPO4/BiOClxBr1-x, improved photoelectrochemical properties are obtained on BiPO4/BiOClxBr1-x. The high performance of BiPO4/BiOClxBr1-x may be attributed to the formation of junction between BiOClxBr1-x and BiPO4, efficiently enhancing charge separation and lowering the recombination rate of photogenerated carriers. The PEC sensor was optimized by adjusting the Cl/Br molar ratio of BiPO4/BiOClxBr1-x. The optimal coupling of the oxidation efficiency and light absorption capacity in various band structures is what causes the 5% BiPO4/BiOCl0.75Br0.25 heterojunction to exhibit the maximum photoelectrochemical activity. The PEC sensor of 5% BiPO4/BiOCl0.75Br0.25 heterojunction presents the low detection limit of 0.11 nM (S/N = 3), and it also exhibits high linear ranges (R2 = 0.9927) of 2–20 μM with good selectivity and stability for the 4-CP detection.