Abstract
A series of hybrid niobates HCa2Nb3O10×RNH2, 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 n-alkylamines. 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 HCa2Nb3O10×BuNH2 reaching apparent quantum efficiency of 13% in the 220–340 nm range. The initial HCa2Nb3O10 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.
Highlights
The intensive consumption of energy resources such as petroleum and coal for the last decades is presently assumed as a reason for environmental degradation and the energy crisis, which forces the development of new renewable and more attractive from the environmental point of view alternative energy sources
According to data of the powder X-ray diffraction (XRD) analysis (Figure 1), protonated layered perovskite-like niobate HCN3·yH2O was successfully obtained in a single-phase form and its lattice parameters were found to be in good consistency with the literature values (Jacobson et al, 1986; Tahara and Sugahara, 2003)
Unlike the Ruddlesden-Popper titanates (Rodionov et al, 2019), this band does not undergo noticeable splitting into two new bands indicating that all niobium-oxygen octahedra adjacent to the interlayer space possess equal axial Nb–O distances, i.e., almost all the interlayer protons of the initial niobate are associated with molecules of amines
Summary
The intensive consumption of energy resources such as petroleum and coal for the last decades is presently assumed as a reason for environmental degradation and the energy crisis, which forces the development of new renewable and more attractive from the environmental point of view alternative energy sources. N-alkylamine Intercalated HCa2Nb3O10 as Photocatalysts the class of layered materials with a perovskite-like structure including Dion–Jacobson (DJ) and Ruddlesden–Popper (RP) phases has been actively studied. Their structure may be presented as an alteration of perovskite blocks and interlayer cations with the general formulae A’[An−1BnO3n+1] (for DJ) and A’2[An−1BnO3n+1] (for RP) (Machida et al, 2005; Compton et al, 2007; Huang et al, 2011; Chen et al, 2012; Rodionov et al, 2012, 2017; Sabio et al, 2012; Zvereva and Rodionov, 2013). These compounds are amenable to reactions involving their interlayer space, such as intercalation and ion exchange, which provide their unique photocatalytic properties (Zvereva et al, 2011; Silyukov et al, 2015; Rodionov et al, 2018; Shelyapina et al, 2019)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
