Bi2Se3/SnSe heterojunction on flexible Ti foil for enhanced photoelectrochemical water splitting

Nanostructured Bi2Se3-Decorated TiSe2 Pyramids on Ti Foil for Photoelectrochemical Water Splitting

“…The PEC measurements were also carried out in 0.5H 2 SO 4 acidic solution at the fixed bias of 0.8 V vs Ag/AgCl for both samples, and it was observed that the current density is almost like that for 0.5 M Na 2 SO 4 electrolyte and decays with time (Figure S5). The comparison of the obtained photocurrent density of various heterostructure photoelectrodes prepared on metal foils with and without CDW materials is shown in Table . ,,− From Table , it is clear that the obtained photocurrent density of the Bi 2 Se 3 -decorated TiSe 2 /Ti electrode is comparable to the available reports on metal foils.…”

“…The positive slope of the curves indicates the n-type conductivity of the samples. To estimate the flat band potential values, the Mott–Schottky equation was used 1 C s 2 = 2 e ε ε 0 A 2 N D ( V − V F B − k normalB T e ) Here, C s is the capacitance, ε is the permittivity of the semiconductor, ε 0 is the permittivity of free space, A is the photoelectrode area, N D is the number of donors, V is the applied voltage, k B is Boltzmann’s constant, T is the absolute temperature, and e is the electronic charge. , A plot of 1/ C s 2 against V yields a straight line, from which V FB can be determined using the intercept on the X -axis. The V FB values of pristine TiSe 2 and Bi 2 Se 3 /TiSe 2 were found to be 0.32 and 0.24 V vs Ag/AgCl, respectively.…”

“…In Figure h, all the XRD peaks of Bi 2 Se 3 are assigned to the rhombohedral crystal structure belonging to the R 3 m space group with lattice constant values of a = 0.414 nm and c = 2.864 nm. The diffracted peaks at 2θ values of 18.3, 25.2, 27.1, 35.5, 37.4, 40.2, 43.3, 45.8, 47.5, and 68.1° can be assigned to the rhombohedral phase of Bi 2 Se 3 (0006), (101), (0009), (018), (00012), (1010), (0111), (116), (00015), and (00021) planes, respectively [JCPDS 33-0214]. ,,, After anchoring the Bi 2 Se 3 film, the XRD peaks of TiSe 2 were found at 28.6, 32.1, 53.2, and 59.8° attributed to the (002), (101), (103), and (104) lattice planes of 1T-TiSe 2 , respectively. It has been observed that the main peak (101) of TiSe 2 in the heterostructure is slightly shifted toward a lower diffraction angle (32.9 to 32.1°) in comparison to that for pristine TiSe 2 , likely due to the presence of tensile strain .…”

“…Among them, two peaks at binding energy peak positions of 54.4 and 53.4 eV are related to the Se 2– valence state in Bi–Se. The single peak at 55.6 eV corresponding to Se 3d 3/2 could be assigned to Se 2– in the Ti–Se bond …”