Synthesis and Photocatalytic Activity of La₅Ti₂Cu(S_1−xSe_x)₅O₇ Solid Solutions for H₂ Production under Visible Light Irradiation

Abstract

Supporting Information and the ORCID identification number(s) for the author(s) of this article can be found under: http://dx.

Effects of Calcination Temperature on the Physical Properties and Hydrogen Evolution Activities of La5Ti2Cu(S1‐xSex)5O7 Photocatalysts

“…The LTCS 1‐ x Se x O solid solutions having higher Se 2− concentrations synthesized at 1273 K exhibited lower H 2 evolution activity under visible light irradiation (λ > 420 nm) . However, the H 2 evolution rates were improved upon decreasing the calcination temperature below 1273 K, irrespective of the Se 2− level.…”

“…The corresponding H 2 evolution time courses are presented in Figure S7 in the Supporting Information. The LTCSO was modified with 1.0 wt% NiS while the other oxysulfoselenide samples were modified with 0.5 wt% NiS by in situ precipitation, using a process optimized in our previous work . The LTCSO sample prepared at 1273 K showed the highest H 2 evolution rate among those specimens prepared at 1173–1323 K. The crystalline phases and the light absorption properties of the samples were largely unchanged and thus would not be responsible for the observed difference in the activity (Figure S1, Supporting Information).…”

“…A reference XRD pattern of LTCSO obtained from Inorganic Crystal Structure Database is also presented in Figure A . Note that the diffraction peaks of LTCS 0.4 Se 0.6 O are located at lower angles because of the expansion of the unit cell . The specimens calcined at 1123–1273 K all exhibit similar XRD patterns attributable to an LTCS 0.4 Se 0.6 O phase.…”

“…The specimens calcined at 1123–1273 K all exhibit similar XRD patterns attributable to an LTCS 0.4 Se 0.6 O phase. The lattice constants of the LTCS 1‐ x Se x O solid solutions follow Vegard's law . Therefore, the lattice constants of LTCS 0.4 Se 0.6 O samples were calculated by Rietveld refinement as shown in Table S1 in the Supporting Information.…”

“…The photocurrent generated by a LTCSO photocathode can be improved by increasing the particle size up to several micrometers as a result of decreases in defect densities and the long‐range diffusion of carriers on the order of micrometers . La 5 Ti 2 Cu(S 1‐ x Se x ) 5 O 7 (LTCS 1‐ x Se x O) solid solutions can also be synthesized by solid‐state reactions . As with many sulfoselenide semiconductors, the absorption edge wavelength of LTCS 1‐ x Se x O increases with increasing Se content .…”