No abstract

The photoelectrochemical behavior of materials based on binary Bi-V oxides was investigated by preparing libraries of ternary metal oxides using high-throughput combinatorial inkjet printing of oxide precursors onto conductive glass substrates. Subsequent pyrolysis of the printed films, with addition of various levels of a third metal oxide precursor, produced libraries of metal oxides that were immersed under potential control into an electrolyte solution and evaluated for water photooxidation or photoreduction activity using a laser scanning technique to produce photocurrent images. It was found that the photoelectrolysis activity of the Bi-V oxides of various stoichiometries was best at a Bi/V ratio of 1 to 1 or the BiVO4 phase. The photocurrent generation of this phase was improved by the addition of various amounts of W, Cu, Fe, Mg, and Mn. Addition of W led to the largest increase in photocurrent of up to 18 times; however the electronic band gap was increased compared to that of unsubstituted BiVO4.

An enhanced photochemical vapor generation (PVG) sample introduction procedure is developed for the determination of trace Bi with inductively coupled plasma mass spectrometry (ICP MS) by the addition of iron. Gas chromatography mass spectrometry (GC−MS) reveals that (CH 3 ) 3 Bi is the major component of the volatile Bi species formed in the presence of 20% (v/v) acetic acid, 5% (v/v) formic acid, and 60 μg mL −1 Fe 3+ under UV irradiation. The addition of Fe 3+ not only largely increases the PVG efficiency of Bi 3+ but also accelerates the reaction kinetics of photochemical reduction of Bi 3+ . The analytical sensitivity was enhanced 30fold using PVG for sample introduction compared to that for direct solution nebulization detection by ICP MS detection. Furthermore, the proposed method shows much better tolerance of interference from Cu 2+ and Ni 2+ than that from conventional hydride generation (HG). Under the optimized conditions, a detection limit of 0.3 ng L −1 was obtained for Bi by ICP MS determination. The relative standard deviation (RSD) was 2.5% for seven replicate measurements of 0.5 ng mL −1 Bi 3+ standard solution. The proposed method has been successfully applied for the determination of Bi in environmental samples, including water samples, and certified reference material of soil (GSS-1) and sediments (GSD-5a and GSD-10) with satisfying results.

No abstract

No abstract