Optimizing study on the NH₃-SCR activity of Ce-W-Ti@g-C₃N₄ catalyst: influence of graphite carbon nitride types

Herein, three g-C₃N₄(MCN/TCN/UCN), obtained by the direct pyrolysis of melamine/urea/thiourea respectively, were introduced as supports to optimize the NH₃-SCR activity of Ce-W-Ti catalyst. Compared to CWT-400-Air, CWT@g-C₃N₄(2)-300-N₂ exhibits lower crystalline anatase TiO₂ and larger specific surface area, which improves the dispersion of Ce/W/Ti species on catalysts surface. Furthermore, the introduction of g-C₃N₄ as supports also contributes to doping C/N elements into Ce-W-Ti catalyst and increases the Ce³⁺/(Ce³⁺+Ce⁴⁺) and O_α/(O_α+O_β) molar ratios on catalyst surface. These all are advantageous to the NH₃-SCR activity. However, UCN shows better promotional effect than MCN and TCN. This might be mainly attributed to the loose and porous stacked layered fold structure of UCN, the larger BET surface area, higher dispersion of Ce/W/Ti species and moderate weak/medium-strong acid sites of CWT@UCN(2)-300-N₂. At the same time, the influence of carbon nitride amount, calcination atmosphere and calcination temperature on the NH₃-SCR activity of CWT@g-C₃N₄ catalyst were also investigated.