Theoretical design of transition metal-doped TiO₂ for the selective catalytic reduction of NO with NH₃ by DFT calculations

Abstract

Many transition metal oxides supported on TiO2 have been studied for selective catalytic reduction (SCR) of NO with NH3. However, the trade-off exists between the low-temperature activity and N2 selectivity....

Understanding the prototype catalyst TiO2 surface with the help of density functional theory calculation

“…230 Zheng et al studied NH 3 adsorption and dissociation on a series of metal-doped TiO 2 (101) surfaces. 228 Compared to that on the clean surface, the adsorption is stronger on the V-, Cr-, Mn-, Mo-TiO 2 , and weaker on the Fe-, Co-, and Ce-TiO 2 . The dissociation barrier on metal-doped TiO 2 is relatively high, except for Co-TiO 2 , which has facile NH 3 dissociation.…”

“…Upon Mn doping on TiO 2 (101) surface, NH 3 adsorbs on the Mn site, and the dissociation becomes less endothermic with a much lower barrier 230 . Zheng et al studied NH 3 adsorption and dissociation on a series of metal‐doped TiO 2 (101) surfaces 228 . Compared to that on the clean surface, the adsorption is stronger on the V‐, Cr‐, Mn‐, Mo‐TiO 2 , and weaker on the Fe‐, Co‐, and Ce‐TiO 2 .…”

“…The dissociative adsorption of NH 3 is less preferred compared to molecular adsorption. On TiO 2 (101) and (001) surfaces, the dissociation is endothermic by 108.3 (or 0.99 eV 228 ) and 30.9 kJ/mol 229 . The dissociation barrier is also much lower on the TiO 2 (001) surface, suggesting that NH 3 dissociation is much easier on the (001) surface than on the (101) surface.…”

“…Deep oxidation of NH 3 , to form N 2 O at high temperature, could reduce the N 2 selectivity. In 2022, Zheng et al further studied the NO reduction with NH 3 catalyzed by (V, Cr, Mn, Fe, Co, Mo, and Ce)‐doped TiO 2 (101) slabs 228 . The obtained activation energies for N 2 and N 2 O suggest that Mn‐, Co‐, Ni‐, Cu‐, Zn‐, Pd‐, Ag‐, and Cd‐doped TiO 2 have good low‐temperature activity, while TiO 2 , Cr‐, Fe‐, Zr‐, and Ce‐doped TiO 2 have high N 2 selectivity.…”

Rational Design of the Catalysts for the Direct Conversion of Methane to Methanol Based on a Descriptor Approach

“…Computational modeling has provided us with a powerful tool, especially in active site identification, intermediate species determination, and reaction path construction [19]. Currently, one of the crucial goals in computational catalysis is to establish and understand structure-activity relationships between the fundamental properties of catalytic materials and their catalytic performance [20], as this understanding will lay the theoretical foundation for achieving a more efficient and rational design of catalysts [21]. Therefore, establishing linear scaling relationships between catalytic performance (e.g., activity, selectivity, and stability) and the physical or chemical properties of the catalytic system (e.g., energy changes, geometric structures, and electronic structures) as descriptors is crucial [22].…”