Supported Pd nanoclusters with enhanced hydrogen spillover for NO_x removal via H₂-SCR: the elimination of “volcano-type” behaviour

Abstract

A rational design of a Pd catalyst with highly dispersed Pd nanoclusters on an Al doped ceria-based oxide for low temperature selective catalytic reduction of NO by hydrogen with excess O was achieved. The supported Pd nanocluster shows a high hydrogen spillover ability and a NO conversion of >84% within 100-300 °C.

Structure, synthesis, and catalytic properties of nanosize cerium-zirconium-based solid solutions in environmental catalysis

“…Moreover, the specific integral reaction rate of Zr-rich W/CZO towards H2-SCR in the range of 250-350 °C was as 2-3 times as that on Ce-rich W/CZO solid. Recently, Li et al [355] prepared a Pd catalyst with highly dispersed Pd nanoclusters on an Al-doped CZO mixed oxide for low-temperature H2-SCR of NOx with excess O2. The introduction of Al into CZO could effectively reduce the crystallite size and enhance the specific surface as well as increase the surficial Ce 3+ concentrations and adsorbed oxygen species.…”

“…Nevertheless, the chemical stability of CH4 implies high activation temperature and, usually, a poor selectivity towards the reduction of NO by CH4 is obtained. Therefore, only a limited number of noble metals can act as the active component, such as Pd [355,[362][363][364][365]. In 2004, Granger et al [366] explored CH4 as alternative in SCR of NO in the presence of oxygen over Pd/CZO under lean conditions.…”

SO2 Resisting Pd‐doped Pr1‐xCexMnO3 Perovskites for Efficient Denitration at Low Temperature

“…Without oxygen participation, the catalyst exhibits excellent efficiency of 73.3 % at 125 °C and a nearly 100 % NO conversion between 150–350 °C. When O 2 was introduced, the decrease of NO conversion in a volcanic curve might result from the competition between O 2 and NO for H 2 , which caused the consumption of reducing agent H 2 in the reaction system [35] . The optimum temperature window shifts to the low‐temperature area with a decrease of O 2 .…”

A promising Al-CeZrO4/HPW-incorporated SPEEK composite membrane with improved proton conductivity and chemical stability for PEM fuel cells

“…The CeZrO 4 and Al-CeZrO 4 supported oxides with a ratio of Ce:Zr = 0.5:0.5 or Al:Ce:Zr = 0.1:0.45:0.45 were prepared using the co-precipitation method. 34 The detailed preparation process is as follows: appropriate amounts of Ce(NO 3 ) 3 ·6H 2 O, ZrOCl 2 ·8H 2 O, Al(NO 3 ) 3 ·9H 2 O as precursors and polyethylene glycol (PEG) as surfactant were dissolved in an ethanol solution at 50°C controlled by a water bath. Ammonium hydroxide was then added dropwise until the pH was greater than 10.…”