Solar energy-driven lignin-first approach to full utilization of lignocellulosic biomass under mild conditions

Visible‐Light‐Driven Cleavage of C−O Linkage for Lignin Valorization to Functionalized Aromatics

“…The photocatalytic activities of Zn m In 2 S m + 3 for the conversion of PP-ol strongly depended on the atomic ratio of Zn/In.Z n 4 In 2 S 7 exhibited significantly highera ctivity than that of other Zn m In 2 S m + 3 photocatalysts;i tw as approximately two times higher than that of ZnIn 2 S 4 .T he yields of AP and Phol increased nearly linearly in the first 2h,t hen further increased to 86 and 82 %, respectively,a fter 4h of reaction( Figure 3a). To comparet he catalytic performance of Zn 4 In 2 S 7 with that of catalysts reported previously in the literature, [19,20] we further synthesized ZnIn 2 S 4 nanosphere (ZnIn 2 S 4 -NS), CdS nanoparticle (CdS-NP), and CdS quantum dot (CdS-QD) photocatalysts, according to methods providedi nthe literature, [19,20] for the catalytic conversion of PP-ol under the same reactionc onditions (Table S3 in the Supporting Information). To comparet he catalytic performance of Zn 4 In 2 S 7 with that of catalysts reported previously in the literature, [19,20] we further synthesized ZnIn 2 S 4 nanosphere (ZnIn 2 S 4 -NS), CdS nanoparticle (CdS-NP), and CdS quantum dot (CdS-QD) photocatalysts, according to methods providedi nthe literature, [19,20] for the catalytic conversion of PP-ol under the same reactionc onditions (Table S3 in the Supporting Information).…”

“…[19,20] The real lignin sample was isolated from birch chips, at ypical hardwood, by as tandard organosolv process with dioxane as as olvent (denoted as dioxasolv birch lignin). Compared with lignin model compounds, the conversion of real lignin is much more difficult, owing to its high molecular weighta nd crosslinked structure.…”

“…[6,12,13] Thus, the development of as ustainable methodology for lignin depolymerization under mild conditions is highly attractive. [17][18][19][20][21] Stephenson and co-workers performed thermocatalytic preoxidation of the C a ÀOH bond of b-O-4 alcohols to b-O-4 ketones,t hen conducted reductivec leavage of the CÀO bondsb yu sing an organometallic iridium photocatalyst. Interestingly,i nr ecent years, several promisingp hotocatalystsh ave been developed for the selectived epolymerization of lignin to value-added chemicals.…”

“…[20] Despite some meaningful progress in photocatalytic lignin depolymerization, strategies for improving the catalyst activity remain limited. CdS quantum dots were furthera pplied for the photocatalytic conversion of native lignin in birch woodmeal to functionalized aromatic monomers.…”

“…[22,23] The positions of the conduction band (CB) and valence band (VB) edges affect the redoxc apability,w hereas the band-gap energy controls the spectralr esponse. [20,21,28] Metal sulfides emiconductors are ac lass of photocatalysts with good visible-light responses, rich variability in properties, and high photocatalytic activities, [29] as well as high potential for selectively cleaving the b-O-4 bond in lignin. [20,21,28] Metal sulfides emiconductors are ac lass of photocatalysts with good visible-light responses, rich variability in properties, and high photocatalytic activities, [29] as well as high potential for selectively cleaving the b-O-4 bond in lignin.…”