A porous bismuth oxyiodide-metal bismuth/nitrogen-doped carbon (BiOI–Bi/N–C) composite composed of BiOI nanosheets, N–C sheets, and metallic Bi nanoparticles was prepared. BiOI–Bi/N–C exhibited remarkable cathodic photoelectrochemical activity and rapid adsorption capacity for Cr(VI) ions. Interestingly, the photocatalytic process of BiOI–Bi/N–C toward Cr(VI) was pH dependent. Under acidic medium, the synthesized material displayed efficient photocatalysis and achieved 95.0% photoreduction efficacy for Cr(VI) ions to Cr³⁺ within 30 min under visible light irradiation. Under neutral medium, Cr(VI) state showed a different photocatalytic process, and Cr(OH)₃ as a product covered on BiOI–Bi/N–C, which decreased the electrochemical (EC) and photoelectrochemical (PEC) performance of BiOI–Bi/N–C. Based on the findings, BiOI–Bi/N–C was utilized as EC/PEC dual-model sensing interface for the detection of Cr(VI) ions. The presented dual-model sensing method displayed an ultralow limit of detection down to 6.8 pM for EC and 3.2 pM for PEC. It demonstrated the practical application potential for the assay of Cr(VI) in real samples.

制备了由 BiOI 纳米片、N-C 片和金属 Bi 纳米粒子组成的多孔碘化铋-金属铋/氮掺杂碳 (BiOI-Bi/N-C) 复合材料。BiOI-Bi/N-C 表现出显着的阴极光电化学活性和对 Cr(VI) 离子的快速吸附能力。有趣的是，BiOI-Bi/N-C 对 Cr(VI) 的光催化过程是 pH 依赖性的。在酸性介质下，合成材料表现出高效的光催化作用，在可见光照射下 30 分钟内Cr(VI) 离子对 Cr ^{3+ 的光还原效率达到 95.0%。}在中性介质下，Cr(VI)态表现出不同的光催化过程，而Cr(OH) ₃作为覆盖在 BiOI–Bi/N–C 上的产物，降低了 BiOI–Bi/N–C 的电化学（EC）和光电化学（PEC）性能。基于这些发现，BiOI–Bi/N–C 被用作 EC/PEC 双模型传感界面，用于检测 Cr(VI) 离子。所提出的双模型传感方法显示超低检测限，EC 低至 6.8 pM，PEC 低至 3.2 pM。它展示了实际样品中 Cr(VI) 测定的实际应用潜力。