Hydrogenated TiO2 Nanoparticles Research Articles

Two-dimensional ultrathin MoS2 modified hydrogenated TiO2 nanoparticles for superior photocatalytic degradation under simulated sunlight

Photocatalysis is an effective technology for degradation of organic contaminants. Herein, we firstly synthesized hydrogenated TiO2 (HT) nanoparticles by calcining P25, and on the basis of HT, two-dimensional ultrathin MoS2/HT binary composites with different component ratios (MHT-20%, MHT-30% and MHT-35%) were controlled prepared. UV–vis diffuse reflectance spectra (DRS) showed that the HT nanoparticles exhibited stronger absorption towards visible light in the range of 550–800 nm compared to P25, and the introduction of two-dimensional ultrathin MoS2 nanosheets further enhanced the visible light absorption ability of MHT composites. Under simulated sunlight irradiation, the removal test of methylene blue (MB) in the present of various photocatalysts indicated that the catalytic performance of HT sample was better than that of P25, and MHT binary composites displayed more excellent photocatalytic performance. A maximum removal efficiency of MB reached 95% within 4 h over MHT-30% photocatalyst. Moreover, the kinetic constant of MHT-30% catalyst is 5.6, 3.6 and 2.5 times as much as that of P25, MoS2 and HT, respectively. In addition, the repeated degradation study and composition analysis of MHT-30% before and after photocatalytic reaction showed that MHT-30% photocatalyst exhibited good stability, and the removal rate of MB still reached 88% in four cycles. The improved and stable photocatalytic performance of MHT-30% can be attributed to band matching and tight interface bonding between MoS2 and HT, which accelerated the electron transfer and broaden the visible-light response range.

Effective hydrogenation of TiO2 photocatalysts with CH3OH for enhanced water splitting: A computational and X-ray study

We have investigated computationally and experimentally the efficacy of CH3OH treatment of anatase TiO2 nanoparticles (NPs) and compared the results obtained with H2 as the hydrogenation source. The results indicate that TiO2 NPs heated at 300 °C in 120 Torr of CH3OH vapor is more effective than the samples heated under 800 Torr of H2 at the same temperature. Ultraviolet-visible spectroscopy (UV-VIS), Photoluminescence spectroscopy (PL) and X-ray diffraction spectroscopy (XRD) were employed to study the optical property. The effect of temperature of hydrogenation has been systematically studied for NPs in the 200–450 °C range for both H-sources based on H2 evolution, employing Xe lamp as the light source. The hydrogenated TiO2 NPs using H2 and CH3OH have been analyzed by soft X-ray absorption near-edge structure analyses with and without Xe lamp irradiation in situ. The result indicates that CH3OH hydrogenation can induce a much stronger TiO interaction along direction dz2 and increase the unoccupied DOS of Ti t2g states. This is why the CH3OH treated TiO2 exhibits a greater photo-activity. The crucial role of the hydrogenation using CH3OH was also investigated systematically and confirmed by quantum-chemical calculations with complementary synchrotron-based X-ray techniques. The results are consistent with the predicted barriers for the formation of H atoms on the TiO2 surface, 4–9 kcal/mol, considerably lower than that in the H2 case, 48 kcal/mol.

Microwave absorption of magnesium/hydrogen-treated titanium dioxide nanoparticles

Abstract Interactions between materials and electromagnetic irradiations in the microwave frequency are critical for many civil and military applications, such as radar detection, communications, information processing and transport et al. Dipole rotations or magnetic domain resonance are the mainly traditional mechanisms for microwave absorption. The recent finding of the excellent microwave absorption from hydrogenated TiO2 nanoparticles provides us an alternative approach for achieving such absorption, by manipulating the structural defects inside nanoparticles through hydrogenation. In this study, we demonstrate that the microwave absorption can be not only achieved but fine-tuned with TiO2 nanoparticles thermally treated in a Mg/H2 environment. Their position and efficiency can be effectively controlled by the treating temperature. Specifically, the microwave absorption position shifts to the lower frequency region as the treating temperature increases, and there seems to exist an optimal treating temperature to obtain the maximum efficiency, as the absorbing efficiency first increases, and then decreases, with the increase in treatment temperature. Therefore, this study enriches our knowledge and understanding microwave absorption from TiO2-based nanomaterials which may inspire new ideas on other systems to enhance their performance as well.

Terahertz absorption of hydrogenated TiO2 nanoparticles

Widely studied as a photocatalytic material for many environmental and clean energy applications, and as an electrode material for solar cells and rechargeable batteries, titanium dioxide (TiO2) has been recently demonstrated as a new microwave absorbing material after hydrogenation. Herein, we report that hydrogenated TiO2 nanoparticles have an efficient terahertz (THz) absorption in a wide THz frequency range between 0.6 and 2.5 THz. With competitive performances over other THz absorbing materials or structures, hydrogenated TiO2 nanomaterials have therefore displayed a bright future for broadband THz absorption and opened a new application for TiO2 nanomaterials.

Interfacial Modification Using Hydrogenated TiO2 Electron‐Selective Layers for High‐Efficiency and Light‐Soaking‐Free Organic Solar Cells

AbstractOptimizing the interfacial contacts between the photoactive layer and the electrodes is an important factor in determining the performance of organic solar cells (OSCs). A charge‐selective layer with tailored electrical properties enhances the charge collection efficiency and interfacial stability. Here, the potential of hydrogenated TiO2 nanoparticles (H‐TiO2 NPs) as an efficient electron‐selective layer (ESL) material in OSCs is reported for the first time. The H‐TiO2 is synthesized by discharge plasma in liquid at atmospheric pressure, which has the benefits of a simple one‐pot synthesis process, rapid and mild reaction conditions, and the capacity for mass production. The H‐TiO2 exhibits high conductivity and favorable energy level formation for efficient electron extraction, providing a basis for an efficient bilayer ESL system composed of conjugated polyelectrolyte/H‐TiO2. Thus, the enhanced charge transport and extraction efficiency with reduced recombination losses at the cathode interfacial contacts is achieved. Moreover, the OSCs composed of H‐TiO2 are almost free of light soaking, which has been reported to severely limit the performance and stability of OSCs based on conventional TiO2 ESLs. Therefore, H‐TiO2 as a new efficient, stable, and cost‐effective ESL material has the potential to open new opportunities for optoelectronic devices.

Enhancing formaldehyde oxidation on iridium catalysts using hydrogenated TiO2 supports

Hydrogenated TiO2 nanoparticles with rich hydroxyls were utilized as robust supports for Ir, accomplishing an obviously improved HCHO oxidation.

Hydrogenated TiO2@reduced graphene oxide sandwich-like nanosheets for high voltage supercapacitor applications

Hydrogenated TiO2 has recently attracted considerable attention as potential electrode materials for supercapacitors due to its abundance, low cost, high conductivity, remarkable rate capability, and outstanding long-term cycling stability. Herein, we demonstrate the synthesis of hydrogenated TiO2 nanoparticles anchored on reduced graphene oxide nanosheets (HTG) in the form of sandwich-like nanosheet composites. Further, we explored their implementation as electrode materials for high voltage, symmetric supercapacitors, operating in the voltage window of 0–1.8 V. The HTGs were prepared by a sol-gel method, followed by hydrogenation in the temperature range 300–500 °C. Of the prepared composites, HTG prepared at 400 °C exhibited the largest specific capacitance of 51 F g−1 at the current density of 1.0 A g−1 and excellent rate capability with 82.5% capacitance retention as the current density increased 40-fold, from 0.5 to 20.0 A g−1. HTG's excellent rate capability was attributed to its sandwich-like nanostructure, in which ultrasmall hydrogenated TiO2 nanoparticles densely anchored onto both surfaces of the two-dimensional reduced graphene oxide sheets. Moreover, HTG-based supercapacitors also exhibited long-term cycling stability with the retention over 80% of its initial capacitance after 10,000 cycles. These properties suggest that HTG is a promising electrode material for the scalable manufacture of high-performance supercapacitors.

Enhancing microwave absorption of TiO2 nanocrystals via hydrogenation

Abstract

Understanding the fast lithium storage performance of hydrogenated TiO2 nanoparticles

Anatase TiO2 is considered as one of the promising anode materials for lithium ion batteries (LIBs) because of its nontoxicity, safety, and excellent capacity retention. However, the poor rate capability of TiO2 electrodes, caused by the low electrical conductivity and lithium diffusion coefficient, strongly hinders its practical application in high power LIBs. Herein, we report on the fast lithium storage performance of hydrogenated anatase TiO2 nanoparticles (H-TiO2) prepared by a H2 plasma treatment. The scan-rate dependence of the cyclic voltammetry (CV) analysis reveals that the improved rate capability of H-TiO2 results from the enhanced contribution of pseudocapacitive lithium storage on the particle surface. Combined with the structural properties of H-TiO2, it is suggested that the disordered surface layers and Ti3+ species of H-TiO2 play an important role in the improvement of pseudocapacitive lithium storage. The results help to understand the fast lithium storage performance of H-TiO2 and might pave the way for further studies of other hydrogenated metal oxide electrodes for high power LIBs.