The Ultrahigh Adsorption Capacity and Excellent Photocatalytic Degradation Activity of Mesoporous CuO with Novel Architecture

Abstract

In this paper, mesoporous CuO with a novel architecture was synthesized through a conventional hydrothermal approach followed by a facile sintering procedure. HR-TEM analysis found that mesoporous CuO with an interconnected pore structure has exposed high-energy crystal planes of (002) and (200). Theoretical calculations indicated that the high-energy crystal planes have superior adsorption capacity for H+ ions, which is critical for the excellent adsorption and remarkable photocatalytic activity of the anionic dye. The adsorption capacity of CuO to methyl orange (MO) at 0.4 g/L was approximately 30% under adsorption equilibrium conditions. We propose a state-changing mechanism to analyze the synergy and mutual restraint relation among the catalyst CuO, H+ ions, dye and H2O2. According to this mechanism, the degradation rate of MO can be elevated 3.5 times only by regulating the MO ratio in three states.

Mesoporous CuO Prepared in a Natural Deep Eutectic Solvent Medium for Effective Photodegradation of Rhodamine B

“…The optical properties of the synthesized CuO NPs were investigated via UV-Vis diffuse reflectance spectroscopy, and the results shown in Figure 5 a and Figures S15–S21 in the Supplementary Materials suggest that the synthesized CuO NPs have good absorption in the visible region; their band gap energy values ( E g , Figure 5 b and Figures S15–S21 ) estimated using Tauc equation (Equation (3)) are in the range of 1.40 eV to 2.47 eV, and are consistent with the reported E g values of CuO NPs [ 3 , 20 , 21 , 22 , 23 ]. ( a h v ) 2 = K (h v − E g ) where K, E g , a ,and h v refer to the constant, the band gap energy, the absorption coefficient, and the photon energy, respectively.…”

“…Cupric oxide (CuO), a p -type semiconductor, with a narrow band gap of about 1.7 eV has been widely used as a photocatalyst in the degradation of organic pollutants, because of its low cost and high efficiency in absorbing sunlight [ 1 , 2 ]. Generally, CuO particles with various structures are synthesized via solvothermal [ 1 , 3 ], ultrasound-assisted [ 4 , 5 ], and microwave assisted [ 6 , 7 ] methods. For example, Sun et al prepared sheet-like CuO using a solvothermal method (reaction time, 12 h; reaction temperature, 80 °C) and the synthesized sheet-like CuO NPs could efficiently activate peroxydisulfate to degrade bisphenol A [ 1 ].…”

“…These results suggested that the synthesis of CuO with enhanced catalytic activity is urgent. Additionally, the preparation of CuO is usually limited by strict experimental conditions (e.g., solvothermal and microwave-assisted techniques usually operate at high temperatures and elevated pressures [ 1 , 3 , 6 , 9 ]) and the use of toxic volatile organic solvents such as dimethylformamide, acetonitrile, and dimethyl sulfoxide [ 4 ]. Therefore, the development of a more straightforward, efficient, and sustainable technique of CuO synthesis using environmentally benign solvents under mild conditions is highly desirable.…”

Biosynthesized Metallic Nanoarchitecture for Photocatalytic Degradation of Emerging Organochlorine and Organophosphate Pollutants: A Review

“…[19] When the pollutant is adsorbed on the surface of the nano-photocatalyst, photocatalytic activity can be enhanced. [20] When selecting an appropriate material for photocatalytic degradation, photoactivity, chemical, and photo stability, and the band gap of the photocatalyst are all factors to be taken into account. [12,21] A wide range of nanoparticles have been effectively used to mitigate the environmental effects of pesticides.…”

“…Solar energy, UV, as well as visible light, are used to irradiate nanosemiconductors, leading to the formation of a variety of radicals, particularly hydroxide and superoxide radicals, that are necessary for photodegradation [19] . When the pollutant is adsorbed on the surface of the nano‐photocatalyst, photocatalytic activity can be enhanced [20] . When selecting an appropriate material for photocatalytic degradation, photo‐activity, chemical, and photo stability, and the band gap of the photocatalyst are all factors to be taken into account [12,21] .…”