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Facilitating the separation of photoexcited electron-hole pairs and enhancing the migration of photogenerated carriers are essential in photocatalytic reaction. CoS/g-C 3 N 4 /NiS ternary photocatalyst was prepared by hydrothermal and physical stirring methods. The optimized ternary composite achieved a hydrogen yield of 1.93 mmol g−1 h−1, 12.8 times that of bare g-C 3 N 4 , with an AQE of 16.4% at 420 nm. The enhanced photocatalytic activity of CoS/g-C 3 N 4 /NiS was mainly ascribed to the synergistic interaction between the Z-scheme heterojunction constructed by CoS and g-C 3 N 4 and the NiS co-catalyst featuring a large amount of hydrogen precipitation sites, which realized the efficient separation and migration of photogenerated carriers. In addition, the CoS/g-C 3 N 4 /NiS heterojunction-co-catalyst system exhibited excellent photocatalytic stability and recyclability. • CoS/g-C 3 N 4 /NiS ternary photocatalyst was prepared by hydrothermal and physical stirring methods. • A large amount of hydrogen precipitation sites are available on CoS/g-C 3 N 4 /NiS ternary photocatalyst. • The Z-scheme heterojunction combined with the co-catalyst promoted the separation and migration of photogenerated carriers. [ABSTRACT FROM AUTHOR]

• Cr and Mn atoms are the main active sites over CrMn 1.5 O 4 (1 0 0) surface. • A reaction scheme for the reduction of NO on the surface of CrMn 1.5 O 4 catalyst is proposed. • The generation of N 2 is accomplished in two main steps. • The energy barrier for the reaction to generate NO 2 is extremely low and contributes significantly to the reduction of NO. A comprehensive study of the catalytic behavior of CrMn 1.5 O 4 catalysts in the selective catalytic reduction (SCR) of nitrogen oxides (NO x) using NH 3 as the reductant was presented. The active sites for NO x reduction and NH 3 adsorption on the CrMn 1.5 O 4 surface were identified by density functional theory (DFT) calculations. The study elucidates the mechanism of NH 3 dehydrogenation and NO reduction, revealing key intermediates and reaction pathways. DFT calculation results showed that the chromium and manganese atoms on the surface, participating in the specifically d − sp hybridization with NH 3 , NO, played a key role in adsorption, and that NH 3 dehydrogenation led to the formation of NH 2 , which was a key intermediate in the selective catalytic reduction reaction. To further understand the process of NO generation to NO 2 and N 2 O on the surface of CrMn 1.5 O 4 catalyst, the chain reaction steps of NO reduction were proposed. Among them, NO was oxidized to NO 2 , and the very low reaction energy barrier contributed greatly to the fast SCR reaction, while the generation of the unwanted product N 2 O had a relatively high energy barrier, so the reaction was not easy to occur. These findings contribute to a deeper understanding of the intricate catalytic behavior of CrMn 1.5 O 4 catalysts, which will aid in the development of better SCR catalysts for the effective removal of NO x in industrial settings. [ABSTRACT FROM AUTHOR]

• MnCoO x @TiO 2 nanocage catalysts derived from the Prussian blue analogue exhibited excellent SCR performance and SO 2 tolerance. • The SCR reaction pathways based on both L-H and E-R mechanisms were investigated. • More ad-NH 3 and ad-NO x species with higher reactivity are available on the surface of the MnCoO x @TiO 2 catalyst. • The synergistic effect of the MnCoO x core and TiO 2 shell is crucial to the SCR reaction and SO 2 resistance. By annealing the self-assembled Mn 3 [Co(CN) 6 ] 2 ·nH 2 O@Ti(OH) 4 , MnCoO x @TiO 2 double-walled nanocage catalysts were obtained. Excellent low-temperature NH 3 -SCR performance (above 90 % NO conversion efficiency at 200–325 °C), acceptable stability, and exceptional SO 2 resistance were demonstrated. According to a series of characterizations, the MnCoO x @TiO 2 catalysts were found to have an enlarged specific surface area, improved surface acidity and redox ability, enhanced dispersion of active components, and abundantly formed adsorbed oxygen (O ads) species, which consequently exhibited the improved deNO x performance. Meanwhile, the coating of the TiO 2 shell reduced the basic sites to adsorb SO 2 , hence leaving a certain proportion of active metal oxides preserved. Apparently, the MnCoO x @TiO 2 catalysts were observed to have an enhanced SO 2 -resistant ability. [ABSTRACT FROM AUTHOR]

A series of Sb-doped CeVO 4 samples were synthetized by hydrothermal method and used in selective catalytic reduction of NO with NH 3. Contrasted with other catalysts, Sb 2 CeVO 4 possessed superior NH 3 -SCR activity and excellent SO 2 tolerance. Besides, the characterization results testified that Sb species in Sb 2 CeVO 4 could reduce the crystallization of CeVO 4 , and improve the surface acidity and reducibility. Moreover, the existence of Sb3+ was beneficial to generate more surface adsorbed oxygen species. Based on the in situ DRIFT spectra, more ad-NH 3 and ad-NO x species with higher reactivity were obtainable on Sb 2 CeVO 4 catalyst compared with that on CeVO 4 catalyst, which also contributed to enhancing the SCR activity by Langmuir-Hinshelwood (L-H) mechanism effectively. Image 1 • Sb modification could improve the SCR performance of CeVO 4 catalyst. • Sb3+ was beneficial to generate more surface adsorbed oxygen species. • More active ad-NH 3 and ad-NO x species were available on Sb 2 CeVO 4 catalyst. [ABSTRACT FROM AUTHOR]

Some fly ash components such as K could seriously weaken the catalytic performance of SCR catalyst. In this study, the core-shell-structured MnFeOx@TiO 2 catalyst is synthesized by dipping deposition method and used for the NH 3 -SCR reaction. The results show that MnFeOx@TiO 2 catalyst exhibits higher K resistance than MnFeOx/TiO 2 catalyst prepared by impregnation method. And the correlativity between the core-shell morphology and K resistance of MnFeOx@TiO 2 catalyst is studied by TEM, N 2 adsorption, XRD, XPS, TPR, TPD and in situ DRIFT. It can be found that the shell of TiO 2 has a protective effect on the active species in MnFeOx@TiO 2 catalyst. And the core-shell structure of MnFeOx@TiO 2 catalyst can produce more Mn4+ and chemisorbed oxygen species on its surface, improving reducibility and surface acidity. Moreover, the core-shell structure of MnFeOx@TiO 2 catalyst is beneficial to the adsorption of NH 3 and the formation of NO 2 , resulting in the favored SCR reaction via the Eley−Rideal and the Langmuir−Hinshelwood routes. Therefore, MnFeOx@TiO 2 catalyst shows excellent K tolerance. Image 1 • The core-shell structure of MnFeOx@TiO 2 catalyst could protect the active species from the contact with K species. • The morphology of MnFeOx@TiO 2 catalyst is propitious to the conversion from to NO 2. • The SCR process over MnFeOx@TiO 2 catalyst was advanced via both E-R and L-H modes. [ABSTRACT FROM AUTHOR]

TiO 2 supported Ce Mo catalyst (Ce Mo/TiO 2) were employed for the first time to simultaneously oxidize elemental mercury (Hg0) and reduce nitrogen monoxide (NO) under simulated SCR atmosphere. The combination of molybdenum oxides and cerium oxides exhibits obvious synergy for Hg0 oxidation and NO reduction. Ce Mo/TiO 2 -0.3 catalyst exhibited an excellent Hg0 oxidation and NO reduction efficiencies of over 90% at above 250 °C corresponding to gas hourly space velocity (GHSV) of 119,000 h−1 (NO reduction) and 1,190,000 h−1 (Hg0 oxidation). Brunauer-Emmett-Teller (BET) surface area was not the dominating factor affecting the Ce Mo/TiO 2 performance. Well-dispersion of active species, abundant chemisorbed oxygen and large surface oxygen capacity were responsible for its high catalytic activity. The presence of Hg0 exhibited a negligible effect on NO reduction. Low-concentration of NO inhibited the Hg0 oxidation while a relatively high concentration had a promotional effect inversely due to abundant NO 2. NH 3 consumed surface oxygen and competed to adsorb with Hg0 resulting in the deactivation of Hg0 oxidation while an excellent recovery was observed after simultaneous cutting off NH 3 and introduction of O 2. In addition, Ce Mo/TiO 2 -0.3 catalyst also presented an excellent resistance to SO 2 and H 2 O poisoning and a good stability and recyclability. The possible mechanism for simultaneous NO reduction and Hg0 oxidation was proposed for Ce Mo/TiO 2 catalysts. The process of NO reduction and Hg0 oxidation over Ce-Mo/TiO2 catalyst. Image 1 • It is the first time that Ce Mo/TiO 2 catalyst was employed for the research of simultaneous Hg0 oxidation and NO reduction. • Low-concentration of NO inhibited the Hg0 oxidation while a relatively high concentration had a promotional effect. • The presence of Hg0 exhibited a negligible effect on NO reduction. • Ce Mo/TiO 2 -0.3 catalyst had an excellent recovery for NH 3 inhibition and resistance to SO 2 poisoning. [ABSTRACT FROM AUTHOR]

In present study, the poisoning mechanism of Cl on V/TiO 2 catalyst for SCR removal of NOx using NH 3 as the reductant was explored by in situ DRIFT technique. The experimental results revealed that the existence of Cl did not change the SCR reaction mechanism over V/TiO 2 catalyst, which was mainly under the control of both E-R and L-H mechanisms. The deactivation of V/TiO 2 catalyst by Cl was mainly resulted from the inhibited adsorption of NH 3 and NOx species, accompanied by the decrease of the reactivity of adsorbed NH 3 species. Image 1 • The addition of Cl on V/TiO 2 catalyst has an inhibition effect on the adsorption of NH 3 and NOx species. • The reactivity of adsorbed NH 3 species over V/TiO 2 catalyst would decrease after the loading of Cl. • The addition of Cl on V/TiO 2 catalyst does not change the mechanism of NH 3 -SCR reaction over it. [ABSTRACT FROM AUTHOR]