Enhanced photocatalytic CO2 reduction to methane over WO3·0.33H2O via Mo doping

Mo‐Doped ZnIn2S4 Flower‐Like Hollow Microspheres for Improved Visible Light‐Driven Hydrogen Evolution

“…Figure S16a, Supporting Information, presents the PL spectra of ZIS, M 0.2 ‐ZIS, and M 3 ‐ZIS. All samples show the broad emission peak centered at 525 nm, which is derived from band‐to‐band transition [11a,21g]. Some weak emission peaks positioned at 419, 450, 468, 482, and 493 nm can also be observed, which are assigned to some defects (e.g., sulfur and zinc vacancy) [21g].…”

“…The characteristic peaks located at about 21.6°, 27.7°, 47.5°, 52.4°, and 55.6° correspond to the (006), (102), (110), (116), and (022) crystal planes, respectively . After Mo doping, the characteristic peaks of Mo‐doped ZnIn 2 S 4 (M‐ZIS) samples slightly shift to higher angles (Figure S5, Supporting Information), illustrating that Mo ions are incorporated into the lattice of ZIS [21d,g,24]. This shift of the characteristic peak is more obvious with the increasing amount of Mo, which can be assigned to the crystal lattice distortion of ZIS caused by Mo doping.…”

“…For ZIS, four Raman peaks around 257, 305, 343, and 379 cm −1 are attributed to the longitudinal optical mode (LO 1 ), transverse optical mode (TO 2 ), longitudinal optical mode (LO 2 ), and A 1g mode of crystalline ZIS, respectively . However, the Raman bands in M 0.2 ‐ZIS assigned to LO 1 , TO 2 , LO 2 , and A 1g shift to 261, 303, 347, and 387 cm −1 , and all the peaks are comparatively weaker, indicating a decreasing crystalline symmetry compared with that of pristine ZIS [21g]. While for M 3 ‐ZIS the peaks at 257 cm −1 disappear, and the peaks at 304, 350, and 387 cm −1 can hardly be observed, which may be due to the doping effect and poor crystallinity …”

“…The photocatalytic water‐splitting performances of ZIS and M 0.2 ‐ZIS samples using different sacrificial agents are shown in Figure S13, Supporting Information. Additionally, we compare the H 2 production activity of Mo‐doped ZIS with other works based on doped ZIS materials (Figure S14, Supporting Information) [16a,21g,24a,29a,35]. To evaluate the photocatalytic stability of the as‐prepared M 0.2 ‐ZIS photocatalyst, the cycling experiments were performed (Figure b).…”

“…Thus, the electronic transitions from the valence band to the dopant level or from the dopant level to the conduction band can effectively broaden the range of light absorption, enhancing solar conversion efficiency . In addition, Mo dopant could induce more active sites, which could localize photogenerated electrons, accelerate photo‐induced electron–hole separation, and boost the transfer of photoexcited electrons to adsorbed reactant molecules, promoting the photocatalytic reaction process . As Mo possesses a suitable ionic size to incorporate the lattice framework of ZIS, but a different d‐electron structure and electronegativity from Zn and In, Mo doping may allow tuning the electronic structure of ZIS and its textual properties.…”