A study on the key factors affecting the sensibility of bismuth deposits toward Sn(2+): Effects of bismuth microstructures on the Sn(2+) pre-deposition

The pre-deposition of Sn following with the square-wave anodic stripping voltammetric (SWASV) analysis is employed to determine the Sn(2+)-sensing ability of bismuth-film electrodes (BFEs). The influences of Bi microstructures, such as grain size, preferred orientation ratio between Bi(110) and Bi(01 2) (denoted as/), and average roughness factor (Ra) of Bi deposits on the Sn(2+)-sensing ability, are investigated. The preferred orientation ratio is a key factor determining the Sn(2+)-sensing ability of BFEs meanwhile a synergistic effect between grain size and/on enhancing the current density of Sn(2+) sensing is obtained when/is above 0.11. The crystalline facet of Bi(110) favorable for pre-depositing Sn is the main reason enhancing the Sn(2+) sensing of Bi deposits. Thus, this work shows that Sn(2+) sensing through stripping of pre-deposited Sn on BFEs does not follow the mechanism of forming Bi-alloy amalgams since the successful pre-deposition of trace Sn(2+) on Bi strongly depends on the effective exposure of crystalline facet of Bi(110).