近日，华北电力大学汪黎东教授团队在国际知名学术期刊
Advanced
Functional Materials
上发表了题为
“
O-bridged
Co-Cu Dual-atom Catalyst Synergistically Triggers Interfacial Proton-coupled
Electron Transfer: A New Approach to Sustainable Decontamination
”
的研究论文。针对碳捕集过程中胺液吸收剂的广泛使用而导致的有机废胺治理难题，本文设计了一种杂原子桥联的双原子催化剂（
DACs
），其具有灵活的活性位点和金属原子间强的相互作用，为高效降解有机废胺提供了新的思路。具体而言，通过简单的两步法制备了一种新型纳米氧化铝负载的氧桥联
Co-Cu
双原子催化剂（
CoOCu-DAC
）。与
Co
单原子催化剂（
Co-SAC
）和块体金属催化剂相比，该催化剂对代表性有机废胺，单乙醇胺（
MEA
，
p
K
a
=9.5
）的去除动力学和过一硫酸盐（
PMS
）利用效率提升了
1-3
个数量级，且性能显著优于已报道的大多数同类体系。通过原位
ATR-FTIR
和理论计算等研究发现，
Cu
的二次引入具有多重关键作用：首先，
Cu
引入激活了与
Cu
和
Co
连接的晶格氧，使得富电子的晶格氧通过亲核攻击触发了
MEAH
+
的关键质子转移（
PT
）；随后，
Cu
吸附去质子化的
MEA
并将其活化为高效的电子供体，通过增强的
Cu-O-Co
轨道重叠加速
MEA
的电子从
Cu
到
Co
…
O
v
位点的转移；最后，在
Co
…
O
v
位点处吸附的
O
₂
与
PMS
捕获转移的电子演变生成各种自由基和非自由基协同攻击界面
MEA
，从而实现了污染物去除效率和
PMS
利用率的双重提升。这种由
CoOCu-DAC
介导的逐步质子耦合电子转移（
PCET
）强化的催化路径，与
Co-SAC
介导的传统类芬顿机制显著不同。建立的二元定量构效关系（
QSAR
）进一步证实了
PCET
增强策略对多种有机废胺的普适性。本研究不仅为碳捕集过程中废胺的高效、低成本治理提供重要的理论与技术参考，也为水体难降解含氮有机污染物的可持续治理提供了新视角
。
图文导读
Figure
1
a)
Aberration-corrected HAADF-STEM image of CoOCu-DAC (Inset is the intensity
profile of the yellow-circled area). b) Elemental mapping for CoOCu-DAC. c, f
and i) XANES spectra, d, g and j) experimental metal K-edge FT-EXAFS spectra.
e, h and k) wavelet transforms spectra. l)
27
Al MAS NMR spectra. m)
Relative formation energy of Cu at possible four substitution positions near to
Co
4c
…
Ov sites on the dominated (110) facet of
γ
-Al
2
O
3
.
Figure
2.
a) MEA degradation curves, b) mass
activity, c) PMS decomposition curves, and d) PUE values over CoOCu-DAC and two
control materials. (Experimental conditions: [MEA] = 50 mg L
–1
,
[cat.] = 0.6
g L
–1
, [PMS] = 5.88
mM). e) Comparison of MEA abatement performance with
reported works. f) Comparison of PUE values. g) Radar diagram of the
physiochemical properties (pore volume, pore size, SSA, Co.wt%, Cu wt.%, Al
wt.%, Ov and Co-O-Cu structure) and catalytic performances of catalyst. The
error bar refers to the standard deviation, calculated at a sample size of 3.
Figure 3.
a-b) MEA degradation curves
in the presence of different quenchers. c) The effect of MEA on radicals
formation. d) The effect of MEA on
1
O
2
production. e) MEA
degradation under the N
2
, O
2
and air (normal)
environments. f) Effect of MEA on PMS decomposition. g) In-situ solid ESR
spectra of CoOCu-DAC after reaction in different suspensions. XPS spectra of
(h-i) CoOCu-DAC and (j) Co-SAC before and after reaction. (Experimental
conditions: [MEA] = 50 mg L
–1
, [cat.] = 0.5
g L
–1
, [PMS] = 4.47
mM). The error bar refers to the standard deviation,
calculated at a sample size of 3
.
Figure
4.
a) In-situ ATR-FTIR during MEA reaction
in CoOCu-DAC/PMS system. b) In-situ ATR-FTIR during MEA adsorption. c) Charge
density differences for CoOCu-DAC and Co-SAC. (ISO value = 0.005 and the yellow
and cyan areas depict charge accumulation and depletion, respectively). d) PDOS
profiles. e) Relative energy of protonated MEAH
+
on two substrates.
f) Charge density difference in optimized configurations of catalysts/MEA
systems (the number of charge transfers from MEA to catalyst are indicated on
the configurations). g) Structure and electron distribution of Co
4c
…
Ov site with/without MEA adsorption. h)
The effect of MEA on O
2
adsorption and activation (ISO value =
0.01). i) Mechanism in two Fenton-like systems.
Figure
5.
a)
k
obs
of different
NOCs over CoOCu-DAC. b) Correlation between p
K
a
, EHOMO and
k
obs
of NOCs in CoOCu-DAC/PMS system. c) Effect of anions, cations, HA and initial
pH values. d) Leaching concentrations of Cu and Co during reaction.
(Experimental conditions: [MEA/pollutant] = 50 mg L
–1
, [cat.] = 0.5
g L
–1
, [PMS] = 4.47
mM). e) Photographs of the operation of the experiment in a
microreactor. f) Efficiency of the continuous flow catalytic process for
removing MEA over a 420 min period. g) The oxidation products of MEA detected
in the continuous experiment. h) Acute and chronic toxicity assessments of MEA
and intermediates. The error bar refers to the standard deviation, calculated
at a sample size of 3.
