Layered Titanate H2Nd2Ti3O10 Intercalated With n-Butylamine: A New Highly Efficient Hybrid Photocatalyst for Hydrogen Production From Aqueous Solutions of Alcohols (original) (raw)
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Frontiers in Chemistry, 2020
A series of hybrid niobates HCa 2 Nb 3 O 10 ×RNH 2 , containing n-alkylamines (R = Me, Et, Pr, Bu, Hx, Oc) intercalated into the interlayer space, has been thoroughly studied concerning the photocatalytic hydrogen production from a model aqueous solution of methanol for the first time. All the hybrid photocatalysts were synthesized by the conventional ceramic technique followed by protonation and intercalation of nalkylamines. The products were characterized using XRD, Raman, IR and diffuse reflectance spectroscopy, TGA, CHN-analysis and SEM. Photocatalytic measurements were conducted according to an advanced scheme taking into account possible changes in the photocatalyst concentration because of sedimentation, pH shifts and exfoliation of the samples into nanoplatelets. Special attention was also paid to the feasible improvement of the photocatalytic activity of the samples via their modification with Pt nanoparticles as a cocatalyst. In the series of amine derivatives, the highest rate of hydrogen generation was demonstrated by the Pt-loaded HCa 2 Nb 3 O 10 ×BuNH 2 reaching apparent quantum efficiency of 13% in the 220-340 nm range. The initial HCa 2 Nb 3 O 10 showed comparable efficiency of 8.3% that is greater than for other amine derivatives. It was demonstrated that for the investigated samples the photocatalytic activity correlates with their ability of water intercalation.
Russian Journal of General Chemistry, 2012
Layered perovskite-type oxides A 2 Ln 2 Ti 3 O 10 (A = Li, Na, K; Ln = La, Nd) prepared by solid-phase synthesis and their hydrated forms were characterized by the methods of TGA, XRD, and by UV-Vis spectroscopy. Photocatalytic activity of A 2 Ln 2 Ti 3 O 10 oxides in reaction of hydrogen evolution from aqueous alcoholic suspensions irradiated by UV-light was studied. It was shown that the ability to intercalation of water into interlayer space essentially affects the rate of photoinduced hydrogen evolution and is a determining factor leading to a high photocatalytic activity.
Catalysts, 2021
A series of hybrid inorganic–organic niobates HCa2Nb3O10×ROH, containing n-alkoxy groups of primary alcohols (R = Me, Et, Pr, Bu, Hx, and Dc) grafted in the interlayer space, has been studied for the first time in relation to photocatalytic hydrogen generation from a model 1 mol % aqueous solution of methanol under ultraviolet irradiation. Photocatalytic activity was measured both for bare samples and for their composites with Pt nanoparticles as a cocatalyst. The advanced measurement scheme allowed monitoring the volume concentration of a sample in a suspension during the experiment, its pH, and possible exfoliation of layered compounds into nanolayers. In the series of n-alkoxy derivatives, the maximum rate of hydrogen evolution was achieved over a Pt-loaded ethoxy derivative HCa2Nb3O10×EtOH/Pt. Its apparent quantum efficiency of 20.6% in the 220–350 nm range was found not to be caused by changes in the light absorption region or specific surface area upon ethanol grafting. Moreov...
High visible light activity of hydrogenated structure-engineered mixed phase titania photocatalyst
Chemical Physics Letters, 2014
The hydrogenation induced band-edge tailing with the resultant red-shift in the absorption spectrum and the creation of oxygen vacancies have incredible impact on the functionality of the monophasic titania photocatalyst in detoxification of aqueous pollutant under solar radiation. The mixed phase titania with optimum phase ratio consistently shows high activity in UV and/or visible radiation flux due to efficient separation of photo-generated charge carriers. We demonstrate that the hydrogenation of mixed phase titania (anatase-to-rutile ratio = 0.67) shows 15 times higher photocatalytic activity in the degradation of aqueous probe pollutant under the visible light, than the non-hydrogenated Degussa P25 catalyst.
Monatshefte für Chemie - Chemical Monthly, 2017
The K 2 La 2 Ti 3 O 10 layered oxide was synthesized by high-temperature technique. Ion exchange properties of K 2 La 2 Ti 3 O 10 ÁH 2 O were investigated by continuous potentiometric titration of its suspension in KOH with HCl. The shape of the titration curve indicates that the ion-exchange reaction of interlayer K ? to H ? proceeds at pH 7.5-8.5 at the rate as high as 5% min-1. Samples obtained during the titration experiment at pH 9.8, 4.8, and 1.4 were examined by XRD, TG, ICP-AES, and SEM-EDX. Protonation already occurs at pH [ 9.8, while at pH 4.8 a substitution degree of 76% is observed. K 2 La 2 Ti 3 O 10 was found to be unstable against K ? leaching, which results in irreversible ion-exchange even when the sample is washed with distilled water. The protonation of the layered oxide significantly suppresses its photocatalytic activity in the reaction of hydrogen production from aqueous isopropanol solution, which correlates with the decreasing amount of intercalated water. Graphical abstract 0.0 0.5 1.0 degree of protonation (x) intercalated water content (y) photocatalytic activity (a.u.) H x K 2-x La 2 Ti 3 O 10 •yH 2 O pH