Citation: Yuqing Chen, Xinxin Liang, Detlef W. Bahnemann, Chuanyi Wang. Boosting α-C bond activation to enable photocatalytic upcycling of waste polylactic acid plastics into value-added pyruvic acid over Au-CdS[J]. Chinese Chemical Letters, ;2026, 37(7): 112645. doi: 10.1016/j.cclet.2026.112645 shu

Boosting α-C bond activation to enable photocatalytic upcycling of waste polylactic acid plastics into value-added pyruvic acid over Au-CdS

Yuqing Chen ^a ,
Xinxin Liang ^a ,
Detlef W. Bahnemann ^{a, b} ,
Chuanyi Wang ^{a, c, *,}

a.
School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi’an 710021, China
b.
Laboratory of Photoactive Nanocomposite Materials, Saint-Petersburg State University, Ulyanovskaya Str. Peterhof, Saint-Petersburg 198504, Russia
c.
Department of Environmental and Sustainable Engineering, Faculty of Engineering, Chulalongkorn University, Pathumwan, Bangkok 10330, Thailand

wangchuanyi@sust.edu.cn

Received Date: 28 October 2025
Revised Date: 22 December 2025
Accepted Date: 19 March 2026
Available Online: 20 March 2026

Figures(5)

Photocatalytic conversion of polylactic acid (PLA) into high-value-added pyruvic acid (PA) presents a promising strategy for carbon-efficient resource cycling. However, successive dehydrogenation at the α-C of lactic acid (the monomer of PLA) remains a critical challenge. In this study, we fabricated an Au-modified CdS nanosphere photocatalyst (Au-CdS), where the introduction of Au facilitates the activation of the C_α-H bond in lactic acid (LA). Through combined theoretical calculations and in-situ EPR analysis, Au-CdS reduces the C_α-H bond cleavage energy barrier from 1.02 eV to 0.49 eV, substantially elevating the generation of carbon-centered radical intermediates. In addition, Au-CdS demonstrates enhanced separation efficiency of photogenerated electron-hole pairs relative to pristine CdS, thus efficiently activating O₂ to generate O₂^•− radicals and further driving the conversion of O₂^•− to ^•OH radicals. The produced ^•OH radicals facilitate the successive dehydrogenation reactions via interacting with the C_α-H and α-OH bonds on the α-C of LA, thereby promoting the selective conversion of LA to PA. As a result, the Au-CdS catalyst achieves a PA production rate of 1340 ± 25 μmol g^-1 h^-1, surpassing that of pristine CdS by 8.9-fold. This work presents a novel strategy for the value-added upcycling of plastic waste.
- Waste plastic,
- PLA,
- Photocatalytic oxidation,
- Au-CdS,
- Value-added exploitation
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