Enhancing Photocatalytic β-O-4 Bond Cleavage in Lignin Model Compounds by Silver-Exchanged Cadmium Sulfide

Article abstract of DOI:10.1021/acscatal.0c01915

Photocatalytic conversion of lignocellulose to valuable aromatics has significant potential for applications in biorefineries. The photocatalyst efficiency of lignocellulose conversion is typically limited by the buffering redox system in combination with oxidation and reduction of the photoexcited holes and electrons, respectively, which ensures high charge-recombination rates. Herein, Ag+-exchanged CdS is employed for easy photoexcited electron transfer to the oxidized intermediate, which results in a marked increase in the conversion yield with high product selectivity under mild reaction conditions without any additives. The conversion yield of the lignin model compound under 6 W blue LED illumination is nearly 100% and only cleaved aromatic compounds are formed. The efficient photoredox CdS catalyst obtained via photoexcited electron-hole coupled transfer derived from an appropriate Ag+ exchange affords a promising method for lignocellulose conversion with reduced energy consumption.

Full text of DOI:10.1021/acscatal.0c01915

Evaluation Only. Created with Aspose.PDF. Copyright 2002-2021 Aspose Pty Ltd.
Subscriber access provided by SAM HOUSTON STATE UNIV
Article
Enhancing Photocatalytic ##-O-4 Bond Cleavage in Lignin
Model Compounds by Silver-Exchanged Cadmium Sulfide
Hyeonji Yoo, Min-Woo Lee, Sunggyu Lee, Jehee Lee,
Soyoung Cho, Hangil Lee, Hyun Gil Cha, and Hyun Sung Kim
ACS Catal., Just Accepted Manuscript • DOI: 10.1021/acscatal.0c01915 • Publication Date (Web): 06 Jul 2020
Downloaded from pubs.acs.org on July 6, 2020
Just Accepted
“Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted
online prior to technical editing, formatting for publication and author proofing. The American Chemical
Society provides “Just Accepted” as a service to the research community to expedite the dissemination
of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in
full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully
peer reviewed, but should not be considered the official version of record. They are citable by the
Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore,
the “Just Accepted” Web site may not include all articles that will be published in the journal. After
a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web
site and published as an ASAP article. Note that technical editing may introduce minor changes
to the manuscript text and/or graphics which could affect content, and all legal disclaimers and
ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or
consequences arising from the use of information contained in these “Just Accepted” manuscripts.
is published by the American Chemical Society. 1155 Sixteenth Street N.W.,
Washington, DC 20036
Published by American Chemical Society. Copyright © American Chemical Society.
However, no copyright claim is made to original U.S. Government works, or works
produced by employees of any Commonwealth realm Crown government in the course
of their duties.

Evaluation Only. Created with Aspose.PDF. Copyright 2002-2021 Aspose Pty Ltd.
Page 1 of 44
ACS Catalysis
1
2
3
4
5
6
7
8
9
Enhancing Photocatalytic -O-4 Bond Cleavage in
Lignin Model Compounds by Silver-Exchanged
Cadmium Sulfide
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Hyeonji Yooa‡, Min-Woo Leeb‡, Sunggyu Leea, Jehee Leec, Soyoung Choc, Hangil Leec*,
Hyun Gil Chab* and Hyun Sung Kima*
a Department of Chemistry, Pukyong National University, Busan 48513, Republic of
Korea
b Bio-based Chemistry Research Center, Korea Research Institute of Chemical
Technology (KRICT), Ulsan 44429, Republic of Korea.
c Department of Chemistry Sookmyung Women’s University, Seoul 04310, Republic of
Korea
*kimhs75@pknu.ac.kr, hgcha@krict.re.kr, easyscan@sookmyung.ac.kr
ACS Paragon Plus Environment
1

Evaluation Only. Created with Aspose.PDF. Copyright 2002-2021 Aspose Pty Ltd.
ACS Catalysis
Page 2 of 44
1
2
3
4
5
KEYWORDS: Biorefinery, Lignin, Photocatalyst, Cadmium sulfide, Silver Ion.
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Abstract
Photocatalytic conversion of lignocellulose to valuable aromatics has significant potential
for applications in biorefineries. The photocatalyst efficiency of lignocellulose conversion
is typically limited by the buffering redox system in combination with oxidation and
reduction of the photoexcited holes and electrons, respectively, which ensures high
charge-recombination rates. Herein, Ag+-exchanged CdS is employed for easy
photoexcited electron transfer to the oxidized intermediate, which results in a marked
increase in the conversion yield with high product selectivity under mild reaction
conditions without any additives. The conversion yield of the lignin model compound
under 6 W blue LED illumination is nearly 100% and forms only cleaved aromatic
compounds. The efficient photoredox CdS catalyst obtained via photoexcited electron–
hole coupled transfer derived from an appropriate Ag+ exchange affords a promising
method for lignocellulose conversion with reduced energy consumption.
ACS Paragon Plus Environment
2

Evaluation Only. Created with Aspose.PDF. Copyright 2002-2021 Aspose Pty Ltd.
Page 3 of 44
ACS Catalysis
1
2
3
4
5
Introduction
6
7
8
9
Biorefineries have recently attracted significant attention for producing abundant and
carbon-neutral renewable energy fuels, which are sustainable alternatives to biofuels and
valuable aromatic chemicals.1,2 Lignocellulose, which is the most abundant aromatic
biopolymer, is a very prospective renewable resource for producing valuable aromatic
monomers.3,4 One of the key issues in lignocellulose conversion is the cleavage of the β-
O-4 bond which constitute around 60% of lignin chemical bonds.5 Therefore, significant
efforts have been directed toward oxidative, reductive, and redox-neutral methods for
cleaving the C−O bonds of the β-O-4 linkages during lignocellulose conversion.6-9
Motivated by the synthesis and decomposition of lignin exposed to sunlight,
photocatalysis is a promising method for lignocellulose conversion because of its reduced
energy consumption, preservation of the aromatic ring as the result of mild reaction
conditions, and high selectivity due to the prevention of thermally-induced side
reactions.10 Therefore, the development of advanced photocatalytic approaches is
particularly important for the selective catalytic valorization of lignin.11-22 In this context, a
two-step photoredox strategy has been widely employed for the conversion of β-O-4 lignin
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
ACS Paragon Plus Environment
3