Fabrication of Opaline ZnO Photonic Crystal Film and Its Slow-Photon Effect on Photoreduction of Carbon Dioxide

Abstract

Monodisperse ZnO particles with adjustable size have been produced on a large scale by two-step seeding-growth polyol reactions. Through spin coating of supersaturated ZnO/diethylene glycol solution and evaporation of solvent, opaline ZnO photonic crystal (PC) film with good crystallinity and uniform photonic structures can be prepared from these ZnO particles. Compared with a disorderly stacked ZnO film, the ZnO PC film shows a higher activity in photocatalytic reduction of CO 2 due to the generated slow photons at the edge of the photonic band gap and their promotion to the light absorption. When the electronic band gap of ZnO matches the red edge of the photonic band gap of ZnO PC, the enhancement factor of photocatalytic activity represented by CO evolution can be maximized to 2.64-fold in the current experiment. Compared to the traditional inverse opal photocatalysts, the opaline ZnO photocatalysts are prepared by simplified and scalable procedures, and they still possess the same enhancement in activity compared to ZnO without the photonic structure, which might be broadly used in solar energy utilization, environment protection, and many other green chemical processes in the future.

Bioinspired Colloidal Photonic Composites: Fabrications and Emerging Applications

“…[ 20 ] The most frequently used organic colloidal particles are PS particles (RI ≈ 1.59) and PMMA particles (RI ≈ 1.50), which can usually be obtained via emulsion polymerization. [ 10b,31 ] PS is a nonpolar polymer, and PS particles can easily aggregate in aqueous suspension due to the lack of electrostatic repulsion. [ ] The introduction of charged comonomers or charged initiators in the polymerization can lead to a series of PS‐based particles, thereby improving their dispersibility to meet the requirements of constructing photonic structures through self‐assembly.…”

Recent Advances in Opal/Inverted Opal Photonic Crystal Photocatalysts

“…[ 62 ] Furthermore, the periodic “opal” templates can direct the infiltration and deposition of precursor materials to yield “inverse opal”. [ 63–66 ] Interestingly, IO PCs with high porosity and periodic interconnected pores can induce slow light [ 67–69 ] and multiple light scattering effects, [ 70,71 ] which favors the light path length extension and absorption efficiency, thus enhancing the photocatalytic performance of the given photocatalyst. [ 72,73 ]…”

Recent advances in constructing heterojunctions of binary semiconductor photocatalysts for visible light responsiveCO2reduction to energy efficient fuels: A review

“…However, ZnO do not response to visible light and suffers from the usual factors that significantly impede its photocatalytic CO 2 activity such as (a) poor visible light absorption; (b) fast recombination; and (c) inferior CO 2 adsorption. 199,[218][219][220][221][222] Intensive endeavors have, therefore, been made to enhance ZnO optical properties by impeding the photoinduced pairs recombination and minimizing the band gap energy. A variety of solutions were proposed to overcome these problems, including the construction of new heterojunctions, 223,224 doping, 225,226 developing new hierarchical structures, 227 and loading of cocatalysts.…”