Exploring Rapid Photocatalytic Degradation of Organic Pollutants with Porous CuO Nanosheets: Synthesis, Dye Removal, and Kinetic Studies at Room Temperature

Abstract

In this work, we report the facile, environmentally friendly, room-temperature (RT) synthesis of porous CuO nanosheets and their application as a photocatalyst to degrade an organic pollutant/food dye using NaBH4 as the reducing agent in an aqueous medium. Ultrahigh-resolution field effect scanning electron microscopy images of CuO displayed a broken nanosheet-like (a length of ∼160 nm, a width of ∼65 nm) morphology, and the lattice strain was estimated to be ∼1.24 × 10–3 using the Williamson–Hall analysis of X-ray diffraction plots. Owing to the strong quantum size confinement effect, CuO nanosheets resulted in an optical energy band gap of ∼1.92 eV, measured using Tauc plots of the ultraviolet–visible (UV–vis) spectrum, resulting in excellent photocatalytic efficiency. The RT synthesized CuO catalyst showed a high Brunauer–Emmet–Teller surface area of 30.88 ± 0.2313 m2/g (a correlation coefficient of 0.99972) with an average Barrett–Joyner–Halenda pore size of ∼20.385 nm. The obtained porous CuO nanosheets exhibited a high crystallinity of 73.5% with a crystallite size of ∼12 nm and was applied as an efficient photocatalyst for degradation of the organic pollutant/food dye, Allura Red AC (AR) dye, as monitored by UV–vis spectrophotometric analysis and evidenced by a color change from red to colorless. From UV–vis spectra, CuO nanosheets exhibited an efficient and ultrafast photocatalytic degradation efficiency of ∼96.99% for the AR dye in an aqueous medium within 6 min at RT. According to the Langmuir–Hinshelwood model, photodegradation reaction kinetics followed a pseudo-first-order reaction with a rate constant of k = 0.524 min–1 and a half-life (t 1/2) of 2.5 min for AR dye degradation in the aqueous medium. The CuO nanosheets showed an outstanding recycling ability for AR degradation and would be highly favorable and an efficient catalyst due to the synergistic effect of high adsorption capability and photodegradation of the food dye.

Advances in the Application of Nanocatalysts in Photocatalytic Processes for the Treatment of Food Dyes: A Review

“…The researchers evaluated the efficiency of nanoparticles obtained by photocatalytic degradation of tartrazine under UVC irradiation and visible light, achieving complete removal of the dye after 90 min. Nazim et al [101] synthesized porous CuO nanosheets using NaBH 4 as a reducing agent in an aqueous medium at room temperature. It achieved an optical energy band gap of 21.92 eV, resulting in excellent photocatalytic efficiency to degrade the food dye Allura Red AC by 96.99% in 6 min.…”

Modifiye MWCNT/CuO Nanokompozitlerinin Optik Özellikleri ve Elektriksel İletkenlikleri Üzerine Non-iyonik Sürfektanın Etkisi

“…Burada, α absorpsiyon katsayısı, h Planck sabiti, ν fotonun frekansı, Eg optik enerji bant aralığı ve B bir sabittir [20,21]. Örneklerin optik bant aralığı değerlerini belirlemek için deneysel eğrilere uyacak şekilde düz çizgiler çizilmiş ve bu çizgiler (ℎν) eksenini kesecek şekilde uzatılmıştır [22].…”

“…Yapıya MWCNT'nin ilavesi ile nanokompozitlerin tahmini optik enerji bant aralıklarının 4,24 eV ile 4,35 eV aralığında değiştiği (Şekil 4) ve CuO nanoparçacıklarının optik enerji bant aralıklarını etkilemediği belirlenmiştir. Bu çalışmada farklı moleküler ağırlığa sahip PEG ve PEGMEMA kullanılarak sentezlenen CuO nanoparçacıklarının ve CNT-M-CuO nanokompozitlerinin optik özellikleri literatürle kıyaslandığında oldukça yüksek bant aralıklarına sahip oldukları görülmektedir [20,[23][24][25][26][27][28][29]. Bu durum, nanomalzemelerin sahip olduğu boyuta bağlı optik özelliklerle sonuçlanan metal oksit yarı iletken malzemelerin nano boyutlu morfolojisinden kaynaklanan kuantum boyutu sınırlama etkilerine atfedilir [20,24].…”

Adsorption performances and electrochemical characteristics of methyl blue onto magnesium-zinc ferrites

“…With the development of human society, dyes were widely applied in textiles, paper, leather, and pharmaceutical industries, etc [1][2][3]. A large amount of dye wastewater was generated, which has caused serious environmental pollution problems and posed a serious threat to human health [4][5][6]. Therefore, there is an urgent need for economical and efficient dye wastewater treatment technology.…”