Fabrication of CdxZn1−xS@VPO (x = 0.2) Nanocomposites for n-Butane Selective Oxidation Toward Maleic Anhydride

Regulation of Maleic Anhydride Selectivity for n-Butane Oxidation by Sb2O3-Modified Vanadium Phosphorus Oxide Catalysts

“…Besides, the characteristic diffraction peaks at 26.6°correspond to the H 0.39 V 2 O 5 phase, which is negatively correlated with MA selectivity. 27 Figure 3c reveals the precursors with orthorhombic Sb 2 O 3 also possessed the main phase of VOHPO 4 •0.5H 2 O. 3,41,42 The characteristic diffraction peaks of 0.5Sb 2 O 3 −O@VPO, 1Sb 2 O 3 −O@VPO, and 2Sb 2 O 3 −O@VPO further confirmed that the (VO) 2 P 2 O 7 phase in catalysts (Figure 3d).…”

“…In addition, the peaks at 977 and 932 cm −1 were attributed to the Vυ (V=O) and Vυ (P−OH) of the precursor, respectively. 27 As shown in Figure 2b, the peaks ranging from 600 to 1300 cm −1 were assigned to the main active phase of (VO) 2 P 2 O 7 in the catalyst. 20 The peaks appearing at 1242 and 1142 cm −1 belong 3,41,42 Besides, the crystal planes of (020), ( 200), (013), and (032) at 2θ = 18.4°, 22.8°, 28.32°, and 29.86°c onfirm the active phase of (VO) 2 P 2 O 7 in the catalysts (Figure 3b).…”

“…3,43 More importantly, the introduced Sb species avoid the formation of the δ-VOPO 4 phase that appeared at 20.82°. 27 Some studies indicated that the δ-VOPO 4 and γ-VOPO 4 phases limited the exposure of active sites on the catalyst surface, thereby reducing the MA selectivity of catalysts. Besides, the characteristic diffraction peaks at 26.6°correspond to the H 0.39 V 2 O 5 phase, which is negatively correlated with MA selectivity.…”

“…However, Sur-O is relatively prone to deep oxidation of the product, thereby reducing the selectivity of MA. 27 The Lat-O/Sur-O ratio was further analyzed and calculated (Table S4). The Lat-O/Sur-O ratio of 1Sb 2 O 3 −O@VPO (12.10) is much higher than that of Blank-VPO (7.77).…”

“…The increased n -butane conversion, MA selectivity, and minimized CO x selectivity can be achieved. Furthermore, VPO can be loaded on the metal oxides (Al 2 O 3, SiO 2, and TiO 2 ), molecular sieves (SBA-15 and MCM-41), and the other supports (SiC and Cd x Zn 1– x S, etc). The supporting materials elaborately regulated the physicochemical properties and structural morphology of the VPO catalysts.…”