Efficiently Engineering Cu-Based Oxide by Surface Embedding of Ce for Selective Catalytic Reduction of NO with NH3
Deliberately engineering oxide composites on constructing and manipulating interactive structures particularly in surface layers was highly desirable for heterogeneous catalysis. Herein, upon the redox replacement reaction between Ce(IV) precursor (Ce(NO 3 ) 6 2 − ) and Cu 2 O nano-substrate, an attempt to directly engineer the surface structure of Cu-based substrate was performed by the Ce(IV)–Cu 2 O etching-embedding process, then the obtained powders were thermo-treated to get a series of Ce–O–Cu catalysts with different Ce:Cu molar ratios for NH 3 selective catalytic reduction (NH 3 -SCR) of NO. Characterized by ICP-OES, XRD, Raman, XPS, SEM, BET, H 2 -TPR, NO- and NH 3 -TPD measurements, it was demonstrated that the Cu–O–Ce catalysts were structured as CuO matrix with an interactive surface composed by co-present Cu(I)–Cu(II) and Ce(III)–Ce(IV) species, even the introduction of Ce was confined in a quite low loading range (0.83–2.3 wt.%); such a surface exhibited the distinct synergistic effect with positively manipulated physical-chemistry properties such as active site distributions, redox features and surface reactivity compared to pure CuO and traditional Cu–Ce composite catalyst, leading to attractive catalytic performance such as ≥ 9 0 % NO conversion with ≥ 9 5 % N 2 selectivity and the two-fold TOF enhancement versus traditional catalysts, even SO 2 was present in reactant mixture on well-manipulated catalyst (Ce loading at 1.6 wt.%) These results indicated that the etching-embedding strategy illuminated in this work could be referred as a feasible method to directly engineer and construct interactive oxide composite surface for advanced application as well as current efficient Ce–O–Cu catalytic interface for heterogeneous catalysis.
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