Ogawa Kanta, Suzuki Hajime, Walsh Aron, Abe Ryu
Centre for Processable Electronics and Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, U.K.
Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan.
Chem Mater. 2023 Jul 12;35(14):5532-5540. doi: 10.1021/acs.chemmater.3c00932. eCollection 2023 Jul 25.
Multicomponent inorganic compounds containing post-transition-metal cations such as Sn, Pb, and Bi are a promising class of photocatalysts, but their structure-property relationships remain difficult to decipher. Here, we report three novel bismuth-based layered oxyiodides, the Sillén-Aurivillius phase BiNbOI, BiBaTiOI, and BiNbWOI. We show that the interlayer Bi-Bi interaction is a key to controlling the electronic structure. The replacement of the halide layer from Cl to I negatively shifts not only the valence band but also the conduction band, thus providing lower electron affinity without sacrificing photoabsorption. The suppressed interlayer chemical interaction between the 6p orbitals of the Bi lone-pair cations reduces the conduction bandwidth. These oxyiodides have narrower band gaps and show much higher water oxidation activities under visible light than their chloride counterparts. The design strategy has not only provided three novel Bi-based photocatalysts for water splitting but also offers a pathway to control the optoelectronic properties of a wider class of lone-pair (nsnp) semiconductors.
含有后过渡金属阳离子（如Sn、Pb和Bi）的多组分无机化合物是一类很有前景的光催化剂，但其结构-性能关系仍难以解读。在此，我们报道了三种新型的铋基层状碘氧化物，即西伦-奥里维利乌斯相BiNbOI、BiBaTiOI和BiNbWOI。我们表明，层间Bi-Bi相互作用是控制电子结构的关键。卤化物层从Cl被I取代不仅使价带负移，也使导带负移，从而在不牺牲光吸收的情况下提供了更低的电子亲和能。Bi孤对阳离子的6p轨道之间被抑制的层间化学相互作用减小了导带带宽。这些碘氧化物具有更窄的带隙，并且在可见光下比它们的氯化物对应物表现出更高的水氧化活性。该设计策略不仅为水分解提供了三种新型的铋基光催化剂，还为控制更广泛的孤对（nsnp）半导体的光电性质提供了一条途径。
