C,N co-doped porous TiO₂hollow sphere visible light photocatalysts for efficient removal of highly toxic phenolic pollutants

Abstract

Herein, C,N co-doped porous TiO2 hollow sphere visible light photocatalysts were fabricated using biocompatible N-lauroyl-l-glutamic acid as a doped precursor and soft-template by a mild and facile self-assembly soft-template method, followed by calcination at 550 °C in air. The structure, morphology, and surface elemental composition were characterized in detail by X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy. The results show that the prepared TiO2 photocatalysts have a porous hollow sphere structure and are co-doped with C and N. The visible-light-driven photocatalytic degradation rates of phenol and 2-chlorophenol are ∼92 and 90%, respectively. The photocatalytic reaction rate constants of phenol and dichlorophen on HPT550 porous TiO2 hollow spheres were about ∼4 and ∼2 times higher than those on P25, respectively. This enhancement is because the C,N co-doped porous TiO2 hollow spheres not only extend the photoresponse to the visible light region as C,N co-doping narrows the bandgap (2.7 eV), but also expose a large number of surface active sites that favor visible-light-driven photocatalysis. Moreover, the porous hollow structure favors multiple reflections of photons in the interior, increasing the utilization ratio of light. It is worth to pay more efforts to the development of visible light photocatalysts and further promote their practical application.

Three-Dimensional Decoupling Co-Catalyst from a Photoabsorbing Semiconductor as a New Strategy To Boost Photoelectrochemical Water Splitting

“…Photoelectrochemical (PEC) water splitting is a promising method to convert solar energy into chemical fuels and has attracted wide scientific interests. To construct a practical PEC device, efficient photoanodes with adequate light absorption, effective charge separation, and high surface reactivity are required. − A high loading of efficient cocatalysts on the surface of a photoabsorbing semiconductor (PAS) is an effective way to enhance the surface reactivity. ,,− However, the aggregation of cocatalyst and decreased light absorption of PAS due to the high loading (Scheme S1A) deteriorate the performance of the PEC cells. Decoupling the PAS with efficient cocatalysts by using a conductive material may offer a way out of this dilemma (Scheme S1B).…”

“…The design prototype was created by homogeneous incorporation of catalytically active transition metal oxides into an in situ formed CP network, which was intergrown and intertwined in the inner space of PAS. The TiO 2 nanorod array was chosen for the demonstrative purpose because it is one of the most widely used materials for PEC water oxidation. − The CP is a phytic acid (for improving the mechanical properties) cross-linked poly pyrrole that is widely used in many fields, − due to its attractive conductivity, redox, and optical properties. , The hierarchical nanostructure of the as-synthesized photoelectrode with abundant FeO x nanoparticles embedded in the CP matrix network (CP-FeO x /TiO 2 ) provides a large number of active sites and facilitates the charge separation/transport, resulting in an advanced PEC water splitting performance. Moreover, this unique 3D decoupling method has been demonstrated to be applicable to various other PAS with different morphologies, suggesting its generality and versatility for improving the performance of photoelectrodes.…”

C,N co-doped TiO2 hollow nanofibers coated stainless steel meshes for oil/water separation and visible light-driven degradation of pollutants

“…As summed by previous researchers, the enhancement in efficiency of TiO 2 based photocatalysts was the result of their anatase crystallinity, high hydrophilicity, surface area and nano tubular morphology 74 . Moreover, some other parameters, such as porous or hollow structure 66 , 75 , 76 and conductive carriers 60 , 62 , 77 , were beneficial to the photocatalytic efficiency of semiconductors. Based on the above discussion, a probable photocatalytic degradation mechanism of methylene blue with TN450 coated mesh is illustrated in Fig.…”

“…To achieve visible light photocatalyst with low price, metal oxide semiconductors, especially TiO 2 based nanomaterials, have been doped with hybrid atoms for low band gap [59][60][61][62][63] . The C,N co-doped TiO 2 exhibits a peculiarly better visible light catalytic activity [64][65][66] . It should be feasible to prepare TiO 2 based membranes with visible light photocatalytic activity and superwetting properties simultaneously.…”

Effect of Calcination Time on the Physicochemical Properties and Photocatalytic Performance of Carbon and Nitrogen Co-Doped TiO2 Nanoparticles

“…The deconvolution of N 1s peak resulted in two distinct peaks as shown in Figure 4c. The peak centred at 397.3 eV for S 1 , 397.1 eV for S 2 and 396.7 eV for S 3 could be from N atoms in O-Ti-N linkages [39]. The other peak at 399.1 eV for S 1 , 398.5 eV for S 2 and 398.3 eV for S 3 were from C=N-C as in pyridine N [39].…”