Advanced nanoporous TiO2 photocatalysts by hydrogen plasma for efficient solar-light photocatalytic application

Abstract

We report an effect involving hydrogen (H2)-plasma-treated nanoporous TiO2(H-TiO2) photocatalysts that improve photocatalytic performance under solar-light illumination. H-TiO2 photocatalysts were prepared by application of hydrogen plasma of assynthesized TiO2(a-TiO2) without annealing process. Compared with the a-TiO2, the H-TiO2 exhibited high anatase/brookite bicrystallinity and a porous structure. Our study demonstrated that H2 plasma is a simple strategy to fabricate H-TiO2 covering a large surface area that offers many active sites for the extension of the adsorption spectra from ultraviolet (UV) to visible range. Notably, the H-TiO2 showed strong ·OH free-radical generation on the TiO2 surface under both UV- and visible-light irradiation with a large responsive surface area, which enhanced photocatalytic efficiency. Under solar-light irradiation, the optimized H-TiO2 120(H2-plasma treatment time: 120 min) photocatalysts showed unprecedentedly excellent removal capability for phenol (Ph), reactive black 5(RB 5), rhodamine B (Rho B) and methylene blue (MB) — approximately four-times higher than those of the other photocatalysts (a-TiO2 and P25) — resulting in complete purification of the water. Such well-purified water (>90%) can utilize culturing of cervical cancer cells (HeLa), breast cancer cells (MCF-7), and keratinocyte cells (HaCaT) while showing minimal cytotoxicity. Significantly, H-TiO2 photocatalysts can be mass-produced and easily processed at room temperature. We believe this novel method can find important environmental and biomedical applications.

Synthesis, properties, and applications of black titanium dioxide nanomaterials

“…Similar conclusions have been drawn in other following studies for black TiO 2 nanomaterials [102][103][104][108][109][110]121,[142][143][144][145][146]. For example, excellent efficiencies were reported for the nanoporous black TiO 2 in photocatalytic degradation of phenol, reactive black 5, rhodamine B, and methylene blue [103]. Excellent photocatalytic activity in the degradation of organic molecules in water was shown by Teng et al [104] with their black TiO 2 prepared by hydrogen plasma assisted chemical vapor deposition.…”

“…Much higher photocatalytic activities in generating H 2 from water-methanol solution and decomposing methylene blue and phenol were reported in the hydrogenated black TiO 2 nanoparticles [87]. Similar conclusions have been drawn in other following studies for black TiO 2 nanomaterials [102][103][104][108][109][110]121,[142][143][144][145][146]. For example, excellent efficiencies were reported for the nanoporous black TiO 2 in photocatalytic degradation of phenol, reactive black 5, rhodamine B, and methylene blue [103].…”

“…Similarly, An et al [103] hydrogenated TiO 2 with a hydrogen plasma. The time was controlled within 0-120 min (H-TiO 2 30, H-TiO 2 120).…”

Band Gap Implications on Nano-TiO2 Surface Modification with Ascorbic Acid for Visible Light-Active Polypropylene Coated Photocatalyst

“…Figure 4 a,b show the peaks deconvolution of XPS spectra for Ti 2p and O 1s respectively. In Figure 4 a (top), for commercial Anatase, two binding energy peaks at 458 and 463.5 eV are observed and are assigned to the Ti 4+ 2p 3/2 and 2p 1/2 core levels, respectively [ 34 , 35 , 36 , 37 ]. Figure 4 a (in the middle) for the pure [TiO 2 ] A heterogeneous photocatalyst shows additional strong peaks at 456.2 and 461.6 eV that are attributed to the Ti 3+ 2p 3/2 and 2p 1/2 respectively formed on the TiO 2 surface [ 38 ].…”

Electrochemical Engineering of Nanoporous Materials

“…Nanoporous materials are outstanding platforms due to their unique chemical and physical properties at the nanoscale, which make them suitable candidates to develop advanced materials and systems for a plethora of applications, including catalysis and photocatalysis [ 1 , 2 , 3 , 4 , 5 , 6 , 7 ], energy harvesting and storage [ 8 ], photonics and optoelectronics [ 9 , 10 ], nanomedicine [ 11 , 12 , 13 , 14 , 15 ], and filtration and separation [ 16 , 17 , 18 ]. Among different methods, electrochemical fabrication techniques offer many advantages over conventional nanofabrication methods to produce nanoporous materials with precisely engineered properties, such as controllability, reproducibility, high resolution, scalability, high-throughput, cost-competitiveness, and time-efficient processes.…”