Efficiently Engineering Cu-Based Oxide by Surface Embedding of Ce for Selective Catalytic Reduction of NO with NH₃

Abstract

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[Formula: see text] and Cu2O nano-substrate, an attempt to directly engineer the surface structure of Cu-based substrate was performed by the Ce(IV)–Cu2O 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 NH3 selective catalytic reduction (NH3-SCR) of NO. Characterized by ICP-OES, XRD, Raman, XPS, SEM, BET, H2-TPR, NO- and NH3-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[Formula: see text]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 [Formula: see text]% NO conversion with [Formula: see text]% N2 selectivity and the two-fold TOF enhancement versus traditional catalysts, even SO2 was present in reactant mixture on well-manipulated catalyst (Ce loading at 1.6[Formula: see text]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.

Boosting CO2 Electroreduction to C2H4 via Unconventional Hybridization: High-Order Ce4+ 4f and O 2p Interaction in Ce-Cu2O for Stabilizing Cu+

“…33 Additionally, four peaks marked as m 0 , m 1 , m′ 0 , and m′ 1 , with BE around 881.3, 885.6, 898.9, and 905 eV, respectively, were attributed to Ce 3+ . 33 Notably, the w′ 0 characteristic peak was ascribed to hybridization configuration of 3d 9 4f 0 (O 2p) Ce 4+ state. 18 The XPS of Ce 3d demonstrates that the valency of the Ce species is mainly composed of Ce 4+ .…”

“…As shown in Figure S1, clear signal peaks of 884.1, 900, and 916.7 eV were detected in the Ce region of Ce-Cu 2 O, whereas no signal of Ce was observed for pure Cu 2 O, indicating successful introduction of Ce species into the Ce-Cu 2 O catalyst. Six peaks, w 0 (BE ≈ 882.6 eV), w 1 (BE ≈ 889.8 eV), w 2 (BE ≈ 897.6 eV), w′ 0 (BE ≈ 901.7 eV), w′ 1 (BE ≈ 908.3 eV), w′ 2 (BE ≈ 916.8 eV), corresponding to Ce 4+ were observed in Figure B . Additionally, four peaks marked as m 0 , m 1 , m′ 0 , and m′ 1 , with BE around 881.3, 885.6, 898.9, and 905 eV, respectively, were attributed to Ce 3+ .…”

“…Six peaks, w 0 (BE ≈ 882.6 eV), w 1 (BE ≈ 889.8 eV), w 2 (BE ≈ 897.6 eV), w′ 0 (BE ≈ 901.7 eV), w′ 1 (BE ≈ 908.3 eV), w′ 2 (BE ≈ 916.8 eV), corresponding to Ce 4+ were observed in Figure B . Additionally, four peaks marked as m 0 , m 1 , m′ 0 , and m′ 1 , with BE around 881.3, 885.6, 898.9, and 905 eV, respectively, were attributed to Ce 3+ . Notably, the w′ 0 characteristic peak was ascribed to hybridization configuration of 3d 9 4f 0 (O 2p) Ce 4+ state .…”

“…Ce-Cu 2 O and pure Cu 2 O catalysts were synthesized using a previously reported reductant coassembly procedure. 33 The crystalline structures of the materials were analyzed by using Xray diffraction (XRD). As depicted in Figure 1A, the diffraction peaks of Ce-Cu 2 O and pure Cu 2 O align well with the pure Cu 2 O phase (JCPDS 65-3288) without any Ce oxide phase detected.…”

“…Ce-Cu 2 O and pure Cu 2 O catalysts were synthesized using a previously reported reductant coassembly procedure . The crystalline structures of the materials were analyzed by using X-ray diffraction (XRD).…”