Plasmonic Bi/COF Nanoheterojunctions for Visible-Light Photodegradation of Phenolic Pollutants

Abstract

Localized surface plasmon resonance (LSPR) is a highly promising method to enhance the catalytic performance of photocatalysts. As an earth-abundant metal element, bismuth (Bi) holds a great promise as an economically feasible substitute for expensive noble metals to prepare metal/semiconductor composite-based plasmon-enhanced photocatalysts, which urgently need promising semiconductors to couple with Bi. Herein, we demonstrate that covalent organic frameworks (COFs) can be used as promising candidates to prepare high-performance Bi/COF plasmonic photocatalysts by providing large numbers of active sites for the in situ growth of non-noble metal Bi, exposing more active sites, and overcoming the problems of low active oxygen utilization and blocked charge transfer. As-prepared Bi/COF nanoheterojunctions not only show increased visible light harvesting, accelerated electron transfer, and retarded charge recombination but also well maintain the strong substrate adsorption capability of COFs, making the photocatalytic reactions work in an adsorption-assisted manner. Via a plasmon-sensitized hot electron injection-based photocatalytic mechanism, the proposed Bi/COF photocatalyst works well in the visible-light photocatalytic degradation of organic pollutants with complete photodegradation of 4-chlorophenol (4-CP) within 70 min. This work not only provides a non-noble metal Bi-based plasmonic photocatalyst with excellent catalytic performance but also paves a promising way to construct adsorption-assisted photocatalytic systems by using COFs.

Applications of bismuth-based nanoparticles for the removal of pollutants in wastewater: a review

“…For instance, the recombination of photogenerated e − and h + on the catalyst surface may occur, leading to a reduction efficiency of photocatalytic reactions. 117,132 Additionally, the optical absorption range of Bi-based NPs is mainly confined to the visible and ultraviolet regions, limiting the utility in photocatalytic applications. Lastly, the limited number and stability of active sites constrain the capture and stable involvement of photogenerated e − and h + in reactions.…”

Na0.5Bi0.5TiO3:Y3+@PAN Nanofibers for Photocatalysis Using Synergetic Piezoelectric Effects

“…In this context, materials that can degrade or convert pollutants using natural energies are being paid more and more attention. For example, photocatalysis, as a green technique of water purification, can break down organic dyes and pollutants into harmless CO 2 or mineralized carbon using solar light. − Meanwhile, piezocatalysis also is a “green” technique based on the piezoelectric effect of part of semiconductor materials without central symmetry and is a combined effect of force and electric polarization, which allows the harvesting of weak mechanical energy even from ultrasonic vibration and water flow. , The piezoelectric effect means that positive/negative charges can be produced on the surfaces to the contrary upon deformation induced by additional pressure along the asymmetry direction. It results in the formation of piezo-potential, which shifts the energetic so that the charges across the piezoelectric/solution interface lead to the degradation of pollutants.…”