Facet Engineering of Bismuth Molybdate via Confined Growth in a Nanoscale Template toward Water Remediation

Abstract

Certain nanomaterials can filter and alter unwanted compounds due to a high surface area, surface reactivity, and microporous structure. Herein, γ-Bi2MoO6 particles are synthesized via a colloidal hydrothermal approach using organically modified Laponite as a template. This organically modified Laponite interlayer serves as a template promoting the growth of the bismuth molybdate crystals in the [010] direction to result in hybrid Laponite–Bi2MoO6 particles terminating predominantly in the {100} crystal facets. This resulted in an increase in particle size from lateral dimensions of <100 nm to micron scale and superior adsorption capacity compared to bismuth molybdate nanoparticles. These {100}-facet terminated particles can load both cationic and anionic dyes on their surfaces near-spontaneously and retain the photocatalytic properties of Bi2MoO6. Furthermore, dye-laden hybrid particles quickly sediment, rendering the task of particle recovery trivial. The adsorption of dyes is completed within minutes, and near-complete photocatalytic degradation of the adsorbed dye in visible light allowed recycling of these particles for multiple cycles of water decontamination. Their adsorption capacity, facile synthesis, good recycling performance, and increased product yield compared to pure bismuth molybdate make them promising materials for environmental remediation. Furthermore, this synthetic approach could be exploited for facet engineering in other Aurivillius-type perovskites and potentially other materials.

Photo-Driven Reduction of Carbon Dioxide: A Sustainable Approach Towards Achieving Carbon Neutrality Goal

“…To promote the separation and transportation of photoinduced charge carriers, Type-II, Z-scheme or p-n heterojunctions are often introduced to the composite photocatalysts to prolong the lifetime of charge carriers so that more electrons can take part in the CO 2 reduction reaction (Jiang et al, 2020;Li S. et al, 2021;Wu et al, 2021). Since CO 2 reduction can only take place on the surface active sites, many recent researches focus on crystal facet engineering in order to maximize the exposure of most active facets (Kong et al, 2018;Jatav et al, 2021). Besides, decreasing the thickness of 2D materials to ultrathin-nanoscale or even atomic layers can endow ultrafast transportation of charge carriers from interior to the surface of photocatalysts along with large exposure of active sites to boost CO 2 adsorption and activation (Han et al, 2021;Teh et al, 2021).…”

Templating Unidirectional Bismuth Oxyiodide Crystal Growth with Layered Silicates for Enhanced Photocatalysis

“…Laponite-RD (Lap) is a magnesiosilicate smectite clay of ∼25 nm diameter and 0.92 nm thickness, which can be easily modified due to its high surface area and cation-exchange capacity. − In previous studies, surfactant-modified Lap has been shown to be a useful template for colloidal nanoparticle synthesis in both exfoliated and pillared states. − The latter tends to lead to the growth of 2D materials with reduced thickness due to the impregnation of the interlayer with nanomaterial precursors. ,, It was also observed that templating the growth of Bi 2 MoO 6 with surfactant-pillared Lap promoted crystal growth along the [010] direction …”

“…31,32,34 It was also observed that templating the growth of Bi 2 MoO 6 with surfactant-pillared Lap promoted crystal growth along the [010] direction. 33 The goal of this study is twofold. First, this represents an effort to achieve templated growth on the basal surface of laponite without cationic surfactants or pillaring of the clay.…”

Surface-Encapsulated Bismuth Molybdate-Layered Silicate Hybrids as Sorbents for Photocatalytic Filtration Membranes

“…33−35 Interestingly, in the case of Bi 2 MoO 6 (BMO), self-assembly of pillared Lap template particles resulted in micrometer-sized particles with surfaces terminating in predominantly {100}-facets, which were found to be effective at quickly sequestering molecular dyes. 36 In addition, their reuse was achieved by photocatalytic degradation of an aqueous particle dispersion following dye adsorption. The characteristics of high adsorption capacity, fast adsorption kinetics, and reuse by photocatalytic degradation motivated further efforts to optimize this system for a real application.…”