Novel mesoporous NiO/HTiNbO5 nanohybrids with high visible-light photocatalytic activity and good biocompatibility

Visible light photoreforming of greenhouse gases by nano Cu-Al LDH intercalated with urea-derived anions

The accumulation of anthropogenic greenhouse gases (GHGs) in the atmosphere causes global warming. Global efforts are carried out to prevent temperature overshooting and limit the increase in the Earth's surface temperature to 1.5 °C. Carbon dioxide and methane are the largest contributors to global warming. We have synthesized copper-aluminium layered double hydroxide (Cu-Al LDH) catalysts by urea hydrolysis under microwave (MW) irradiation. The effect of MW power, urea concentration, and MII/MIII ratios was studied. The physicochemical properties of the prepared LDH catalysts were characterized by several analysis techniques. The results confirmed the formation of the layered structure with the intercalation of urea-derived anions. The urea-derived anions enhanced the optical and photocatalytic properties of the nano Cu-Al LDH in the visible-light region. The photocatalytic activity of the prepared Cu-Al LDH catalysts was tested for greenhouse gas conversion (CH4, CO2, and H2O) under visible light. The dynamic gas mixture flow can pass through the reactor at room temperature under atmospheric pressure. The results show a high conversion percentage for both CO2 and CH4. The highest converted amounts were 7.48 and 1.02 mmol mL-1 g-1 for CH4 and CO2, respectively, under the reaction conditions. The main product was formaldehyde with high selectivity (>99%). The results also show the stability of the catalysts over several cycles. The current work represents a green chemistry approach for efficient photocatalyst synthesis, visible light utilization, and GHGs' conversion into a valuable product.

Adsorption and Separation of Ethyl Mercaptan from Methane by Hydroxyl Groups on the Surface of HTiNbO5-Nanosheets

Adsorption and separation of light mercaptan (R-SH, R = C₁-C₄) from methane gas can effectively improve the utilization efficiency of methane and the resource conversion of organic sulfide. To further investigate the effects of composition and structural characteristics of laminates on desulfurization performance, in this paper, a two-dimensional (2D) HTiNbO₅-nanosheet (HTiNbO₅-NS) was constructed. In addition, the hydrogen-bonding interaction between the exposed hydroxyl active sites on the surface of HTiNbO₅-NS and ethyl mercaptan (Et-SH) was constructed to realize the adsorption and separation of Et-SH from methane gas. The breakthrough adsorption capacity (C_ap (BT)) of HTiNbO₅-NS is 14.35 mg·g^-1 in a micro fixed bed with a space velocity of 6000 h^-1. The regeneration desulfurization rate (q) of the 10-cycle regeneration adsorption was ca. 96%. Furthermore, density functional theory (DFT) calculation results show that the S atoms of Et-SH and HTiNbO₅-NS with the terminal hydroxyl and bridge hydroxyl have electron cloud covering to form the hydrogen-bonding interaction. In addition, the formation details of this hydrogen-bond interaction are discussed. The effects of Ti on the microstructure, hydroxyl acid, hydroxyl content, surface area, and pore volume of nanosheets were studied to explain the reasons for the differences in the properties of the two kinds of nanosheets. This work broadens the design of 2D niobium-based efficient adsorbents for R-SH based on hydrogen-bonding interaction and is helpful to enrich the application of the hydrogen-bonding interaction.

Ultrathin Z-scheme 2D/2D N-doped HTiNbO5 nanosheets/g-C3N4 porous composites for efficient photocatalytic degradation and H2 generation under visible light

To realize highly efficient utilization of solar energy for solving problems of environmental pollution and energy shortage has attracted increasing attention. Herein, a two-step exfoliation-restacking process was employed to construct ultrathin Z-scheme two-dimensional (2D)/2D N-doped HTiNbO₅ nanosheets/g-C₃N₄ (RTCN) heterojunction composites with the increased specific surface areas, showing the enhanced photocatalytic performance for rhodamine B (RhB) degradation and hydrogen (H₂) generation under visible light irradiation. A 2D/2D heterojunction structure was formed between N-doped H⁺-restacked HTiNbO₅ nanosheets (N-RTNS) and g-C₃N₄, which was beneficial for the effectively spatial separation of photogenerated charge carriers. The improved photocatalytic activities may be attributed to the synergistic effects of the increased specific surface area, N-doping and 2D/2D heterostructure. The active species of holes (h⁺), hydroxyl (•OH) and superoxide (•O₂^-) radicals contributed to RhB photodegradation. A Z-scheme photocatalytic mechanism was proposed over RTCN-2 composite, showing dual advantages of the highly redox ability and efficient charge carrier separation.

Synthesis, characterization and enhanced visible-light photocatalytic activity of novel NiO/HTi2NbO7nanocomposite

The decreased electron–hole recombination rate of the NiO/HTi₂NbO₇nanocomposite plays a crucial role in improving visible-light photocatalytic activity.

The impact of nitrogen doping and reduced-niobium self-doping on the photocatalytic activity of ultra-thin Nb3O8− nanosheets

Ultra-thin [Nb₃O₈]⁻ nanosheets with N doping, reduced-Nb doping and N/reduced-Nb codoping were fabricated by combining chemically controlled syntheses and liquid exfoliation, which enable comparative studies on the doping effect for photocatalytic H₂ evolution.

S-doped mesoporous nanocomposite of HTiNbO5 nanosheets and TiO2 nanoparticles with enhanced visible light photocatalytic activity

S-doped mesoporous TiO₂/HTiNbO₅ nanocomposite showed dramatically enhanced visible-light photocatalytic activity and stability owing to the combined effects of nano-heterojunction, S doping and morphology engineering.

S-doped Na2Ti6O13@TiO2 core–shell nanorods with enhanced visible light photocatalytic performance

S-doped Na₂Ti₆O₁₃@TiO₂ core–shell nanorods with exposed anatase {101} facets showed enhanced visible-light photocatalytic activity and stability for the degradation of methylene blue owing to the combined effect of hybridization, morphology engineering and S doping.

The nanocomposite of polyaniline and nitrogen-doped layered HTiNbO5with excellent visible-light photocatalytic performance

N-doping and intercalation resulted in a PANI–N-HTiNbO₅lamellar nanocomposite, which showed a dramatic enhanced visible-light photocatalytic activity and stability for the degradation of methylene blue (MB), due to the high efficiency of charge separation.