Table 1.

Nomenclature and properties of MoO_x-TiO₂ catalysts

Catalyst	Mo loading [wt%][a]	Mo surface density [atoms/nm2][b]	Absorption edge energy [AEE, eV][c]	Ethanol conversion [mol%][d]	Acetaldehyde selectivity [mol%][e]
1	1.96	1.11	3.61	10.1	88.5
2	3.91	2.23	3.47	19.8	85.5
3	6.96	3.97	3.19	29.8	78.2
4	10.0	5.71	3.06	36.1	79.1
5	13.9	7.94	2.89	41.4	69.8
MoO3/TiO2[f]	5.3 (MoO3)	4.8	n/d	17	94
VOx/TiO2/SiO2[g]	2.3 (V2O5)	0.9	n/d	∼15	∼95
V2O5/TiO2[h]	15 (V2O5)	7.7	n/d	∼85	∼95
Mo–Ce–Sn–O[i]	8% Mo, 1%Ce	4.03	n/d	∼81	∼75

^[a]Nominal loading.

^[b]Calculated from the Mo loading and BET surface area; provides a theoretical estimate of MoO_x species per unit area (nm⁻²) of the catalyst.

^[c]Calculated from UV-Vis DRS spectra.

^[d]Continuous steady-state conversion at 150 °C observed over 1 h; determined by GC as moles of ethanol reacted per mole of ethanol fed.

^[e]GC selectivity determined as moles of a particular product formed per mole of all products formed.

^[f]Ethanol:O₂:H₂O:He:N₂=1:3.3:10:35.3:0.34; total pressure: 1.6 MPa, T=200 °C.⁹

^[g]Molar composition: 1.4% EtOH vapour, 28.0% O₂ and balance N₂. W/F=11.7 g catalyst×h mol⁻¹ of ethanol. T=140 °C; surface density based on V atoms/nm²; VO_x denotes that the exact nature of vanadium containing species is unclear.¹⁶

^[h]P=2.7 bar, GHSV=25000 h⁻¹, O₂/ethanol mole ratio=3.3; T=175 °C; surface density based on V atoms per square nm.¹¹

^[i]3% ethanol/air (vol.%) mixture, space velocity=11520 h⁻¹; T=150 °C.⁸