Surface and Defect Engineering Coupling of Halide Double Perovskite Cs₂NaBiCl₆ for Efficient CO₂ Photoreduction

Abstract

amounts of greenhouse gases, leading to global warming. Widely distributed solar energy is the most abundant and cleanest energy on the earth. Therefore, the conversion of carbon dioxide into renewable hydrocarbons through solar light-driven photocatalysts is an effective strategy to mitigate the environmental crisis. [1,2] Photocatalytic materials have been widely developed since Fujishima's pioneering research work on photocatalytic decomposition of water was reported in 1972. [3] However, single-component semiconductor photocatalysts show low photocatalytic activity due to their rapid charge carrier recombination. Therefore, the development of efficient, inexpensive, and stable photocatalysts has become the key to this technology.In the past few years, perovskite materials have shown excellent photoelectric performance in important research fields such as light-emitting diodes [4,5] and solar cells, [6,7] indicating that perovskite materials have excellent photogenerated charge-carrier generation capabilities. Therefore, they are equally promising for photocatalytic applications. In recent years, halide perovskite nanocrystals have been proved to be capable of photocatalytic CO 2 reduction and the photocatalytic property has been improved by many approaches. [8][9][10] For example, Kong et al. [11] found that in-situ growth of metal-organic framework on the surface of CsPbBr 3 quantum dots can significantly enhance the photocatalytic CO 2 reduction ability. Xu et al. [12] achieved more efficient CO 2 photochemical conversion by composing CsPbBr 3 quantum dots and graphene oxide. However, the poor stability in high humidity or oxygen-rich environment and lead toxicity severely limit their applications. [13,14] Recently, relatively more stable lead-free perovskite materials have likewise shown promising prospects for photocatalytic CO 2 reduction, such as Cs

Enhanced Photoelectrocatalytic Water Splitting in Bi2Mo1–xWxO6 Solid Solutions: Understanding the Atomic Level Mechanism from the Experimental and First-Principles Approach

“…The effect of bandgap on W incorporation was studied by UV–vis diffuse reflectance and the results are shown in Figure a; the Bi 2 MoO 6 and Bi 2 WO 6 have absorption edges of 480 and 440 nm, and calculated bandgap energy of 2.65 and 2.83 eV respectively (eq S4). Upon introducing W, the absorption edges of Bi 2 Mo 1– x W x O 6 solid solutions show the redshift, but the change is very minimal and the results correlate well with previous reports. ,, Moreover, the CBM and VBM of Bi 2 Mo 1– x W x O 6 solid solutions were calculated (eqs S5–S6) from results of Mott–Schottky plots (Figure S7) and XPS valence band analysis ,− (Figure S8) and results are given in Figure c and Table S3, which indicates that when the small amount of Mo replaced by W there is no appreciable change in the band structure; meanwhile, it suggests that the influence of W is higher in the conduction band states than the valence band, which is further confirmed by the band structure analysis using DFT calculations. The DFT results clearly explain that the VBM of the Bi 2 MoO 6 and Bi 2 WO 6 mainly consists of O-2p and Bi-6s orbitals and CBM mainly originated from Mo-4d or/and W-5d orbitals, respectively.…”

Halide perovskite quantum dots for photocatalytic CO2reduction

“…To solve this problem, some Pb-free perovskite QDs have been obtained, such as Cs 2 SnI 6 , 126,127 Cs 2 AgBiX 6 , 128 and Cs 2 NaBiCl 6 . 129 Nonetheless, the photocatalytic CO 2 activities of these substitutions are lower than that of Pb-based perovskite QDs. As a result, much attention should be paid to finding stable low-toxic or non-toxic perovskite materials with high catalytic performance.…”

Interfacial electronic and vacancy defect engineering coupling of the Z-scheme CsSnBr3/SnS2 heterostructure for photovoltaic performance: a hybrid DFT study

“…However, defects are inevitable in the process of preparing materials, which signicantly inuence the photovoltaic performance of materials. 30 On one hand, the local energy levels introduced by the defects can modulate the energy band structure and enhance the light absorption of semiconductor materials; on the other hand, defects can act as electron capture centers, provide electrons on the material surface, and promote the separation of photogenerated electron-hole pairs. 31,32 Yue et al reported that Cs 2 AgBiBr 6 with bromine (Br)-vacancy exhibits strong stability, the defects could optimize its electronic structure and enhance charge separation, leading to improved photocatalytic performance.…”