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A series of ceria modified CuO/γ-Al 2 O 3 (CuO-CeO 2 /γ-Al 2 O 3 ) catalysts were prepared via stepwise impregnation (CuCeAl-SI) and co-impregnation (CuCeAl-CI) method and tested in the model reaction of NO reduction by CO. It was found that the influence of impregnation modes on the catalytic properties of CuCeAl samples mainly lies on the control of ceria particle sizes and modulation of the distribution of various copper species. In both impregnation modes, ceria was mainly spread on γ-Al 2 O 3 as small particles while copper species were highly dispersed. A quantitative estimation of copper species was tentatively provided via a combined surface acid leaching experiment and H 2 -TPR characterization for the first time. The results showed that for CuCeAl-CI catalyst, about 55% and 25% copper species were dispersed on γ-Al 2 O 3 and nanosized ceria, respectively, while about 20% was migrated into ceria lattice during the calcination process. In contrast, in CuCeAl-SI sample, the corresponding values changed to about 25%, 70% and 5%, respectively. The synergistic effect between copper species and ceria can promote the improvement of catalytic performance, which results in higher activity of CuCeAl-SI than that of CuCeAl-CI catalyst. [ABSTRACT FROM AUTHOR]

Highlights: [•] CuO-CeO2/SBA-15 catalysts were prepared by a novel solid state impregnation method. [•] Both copper species and ceria can be well dispersed. [•] In comparison with wet impregnation, the solid state impregnation derived catalyst owns increased interfacial CuO-CeO2 entities and enhanced interfacial interactions. [•] CuO-CeO2/SBA-15 catalyst from solid state impregnation shows enhanced CO-PROX activity and good tolerance to CO2 and H2O. [Copyright &y& Elsevier]

Monolithic Mn-Fe-Ce-Al-O catalyst with honeycomb cordierite ceramic as a carrier was reported for the first time for low temperature deNOx application. In the reaction of selective catalytic reduction (SCR) of NO with NH3, a NO conversion of above 80% at 100 °C was obtained. Notably, the catalyst also showed excellent resistance against SO2 and H2O. About 60% NO conversion was maintained after successive operation in the mixed stream of SO2 and H2O for 168 h. The Brunner−Emmet−Teller (BET) measurement, SEM, EDS, thermogravimetric analysis (TG), FT-IR, and XPS results of the used catalysts indicated that certain amounts of ammonium sulfate was formed on the surface of the catalyst. XPS results revealed that partial of Fe2+ was oxidized to Fe3+ during the reaction process, and Fe2+ species have strong redox ability, which can explain the decrease in activity after reaction. In addition, SO2 and H2O induced a transformation of Ce from Ce4+ to Ce3+ on the surface of the catalyst, which increased the amount of chemisorbed oxygen. Owing to these factors, the addition of Ce and Fe species contributes to excellent resistance of the catalyst to SO2 and H2O. [ABSTRACT FROM AUTHOR]

Modifying CeO 2 with acid sites is a common strategy for designing efficient catalysts for the selective catalytic reduction of NO x by NH 3 (NH 3 -SCR of NO x). However, the effect of acid metal oxide modification on the SO 2 resistance of CeO 2 has not been well revealed. In this work, it was found that the SO 2 resistance of CeO 2 modified with several acid metal oxides (i.e. , MoO 3 , WO 3 and Nb 2 O 5), followed an order of Mo/CeO 2 ≥ W/CeO 2 > Nb/CeO 2. Further systematic characterizations revealed that Mo-OH and W-OH on CeO 2 as Brønsted acid sites could better inhibit the SO 2 adsorption and the sulfation of active sites than highly dispersed NbO x mainly as Lewis acid sites because NH 4 + coordinated to Brønsted acid sites could help trap SO 2 to form ammonium sulfates rather than metal sulfates. The findings in this work provided important guidance for the design of efficient catalysts with superior SO 2 resistance performance. [Display omitted] • CeO 2 modified with varying acid metal oxides showed different resistance to SO 2. • Highly dispersed MoO 3 or WO 3 could better shield CeO 2 from SO 2 poisoning than Nb 2 O 5. • Mo and W sites as Brønsted acid sites could better inhibit the SO 2 adsorption on CeO 2. • SO 2 could interact with both highly dispersed Nb 2 O 5 and CeO 2 on Nb/CeO 2. • A strategy for designing efficient catalysts with superior resistance to SO 2 was provided. [ABSTRACT FROM AUTHOR]

In this work, CeO 2 nanocubes hybridized g-C 3 N 4 composites had been facilely synthesized to investigate the interfacial effects on photocatalytic water splitting. The c-CeO 2 /g-C 3 N 4 composites exhibited the superior photocatalytic hydrogen evolution under visible light irradiation. The optimal c-CeO 2 loading content was 5 wt%, with the H 2 evolution of 4300 μmol g −1 for 5 h illumination, higher than that of pristine CeO 2 , g-C 3 N 4 and irregular CeO 2 nanoparticles/g-C 3 N 4 . Moreover, UV–vis DRS, PL spectra and photoelectrochemical measurements demonstrated that 5 wt% c-CeO 2 /g-C 3 N 4 composite possessed more visible light adsorption and faster charge transfer, which was attributed to the stronger interfacial effects through the presence of the hydrogen bond and p-π hybrid between c-CeO 2 {100} and g-C 3 N 4 , revealed by the FT-IR and XPS results. The work suggested that engineering the structures of the CeO 2 and g-C 3 N 4 interface could be an effective strategy to obtain excellent photocatalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel hybrid strategy is employed to design catalysts with superior K resistance. • The main reason for CeMn deactivation is cut-off of L-H mechanism resulting from the formation of stable nitrates. • The addition of ZSM-5 can re-activate the inert nitrates. • Alkali metals poisoned catalysts can be regenerated by ZSM-5 hybridization. The application of cerium-manganese oxides (CeMn) in controlling exhaust gas from biomass combustion is greatly inhibited due to poor resistance to alkali metals. Herein, we report a smart strategy to circumvent the K poisoning problem of CeMn by physically coupling with ZSM-5, which exhibited almost no activity loss even under a high loading of 2 wt % K 2 O. Results showed that in contrast to the conventionally believed disturbance of redox property and reduction of acid sites, the dominant effect from K loading on the deactivation of CeMn catalysts lies on the formation of chemically inert nitrates, which significantly restrains the reaction cycle via Langmuir-Hinshelwood route. With ZSM-5 hybridization, the stable nitrates over CeMn can be facilely activated and consumed by NH 4 + species introduced by ZSM-5, thus transforming poisoning sites into active sites and ensuring superior catalytic performance. The study presenting here not only provides an efficient strategy for fabricating NH 3 -SCR catalysts with superior K resistance but also sheds new light on the deactivation mechanism of K over CeMn catalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Pt x Ir alloy nanoparticles were fabricated via ethylene glycol reduction method. • The Pt 2.5 Ir/CeO 2 catalysts shows an excellent activity for toluene combustion. • The Pt 2.5 Ir/CeO 2 has abundant oxygen vacancies and the best reducibility. • The interaction between Pt and Ir is helpful for the best activity of Pt 2.5 Ir/CeO 2. • The possible reaction pathway over Pt 2.5 Ir/CeO 2 is studied by the in-situ DRIFTS. Herein, bimetallic Pt-Ir alloy nanoparticles (NPs) were successfully fabricated by ethylene glycol reduction of H 2 PtCl 6 ·6H 2 O and IrCl 3 through a microwave-assisted method. The Pt-Ir alloy NPs were deposited on CeO 2 catalysts for toluene combustion. The Pt 2.5 Ir/CeO 2 sample exhibited better catalytic activity at low reaction temperature, compared with monometallic catalysts. The excellent low-temperature catalytic activity was resulted from the interaction between Pt and Ir, richer adsorbed oxygen species and low-temperature reducibility. Furthermore, the in-situ DRIFTS was used to investigate the possible reaction pathway of Pt 2.5 Ir/CeO 2. It showed that the broken of benzene ring on Pt 2.5 Ir/CeO 2 can be accomplished at lower temperature, resulting in enhancing the deep oxidation of toluene. [ABSTRACT FROM AUTHOR]