Photothermal catalysis of waste plastics into propionic acid and hydrogen via Ni single- atom site isolation effect

• 成果类型: Article
• 署名作者: Yue, Shuai; Liu, Yixiao; Zhao, Zhiyong; Zhao, Guanshu; Yang, Mengxue; Zhang, Tao; Li, Fei; Liu, Kewang; Wang, Pengfei; Zhan, Sihui; Jia, Jinhu
• 署名单位: Nankai University; University of Toronto; Tianjin University
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-15254
• DOI: 10.1073/pnas.2508636122
• 发表日期: 2025-07-01
• 关键词: conversion; BEHAVIOR

摘要

Currently, catalytic recycling of polyethylene (PE) into high-value chemicals using solar energy often faces poor product selectivity and low efficiency. This is mainly due to the difficulty in effectively controlling the intermediates during PE photoreforming and the long-standing challenge of inefficient charge dynamics. Here, we present a solar-driven photothermal catalytic approach for the selective conversion of PE waste into propionic acid and hydrogen under ambient conditions. Atomically dispersed Ni sites supported on CeO2 (NiSA/CeO2) achieve a propionic acid yield of 331 mu mol h-1 with 94.8% selectivity in the photothermal reaction. This performance is 1.6 times higher than that of catalysts supported by Ni clusters (NiNP/CeO2). Additionally, NiSA/ CeO2 exhibits a hydrogen yield of 0.23 mmol h-1 with stable long-term performance. Mechanistic studies reveal that single Ni atoms form linear coordination with oxygen atoms in CeO2, introducing unoccupied mid-gap states that effectively capture hot electrons and enhance the photothermal effect through local hotspot formation. In contrast, Ni clusters suffer from inefficient heat accumulation due to multistep phonon scattering. Furthermore, site isolation of Ni single atoms spatially separates the reaction intermediates and suppresses dimerization of the key intermediate COOHCH2CH2*, thereby greatly improving the selectivity for propionic acid. In contrast, closely packed Ni cluster sites promote intermediate coupling and the formation of undesirable byproducts, reducing selectivity. This work provides mechanistic insights into the advantages of atomic-scale catalyst design for selective chemical transformations. Significance This study presents a solar-driven photothermal catalytic method for converting polyethylene waste into propionic acid and hydrogen under ambient conditions. Using atomically dispersed Ni sites on CeO2, we achieved a 1.6 times higher propionic acid yield and stable long-term hydrogen production compared to Ni cluster catalysts. This approach enhances selectivity and provides a scalable, sustainable alternative to traditional recycling methods, with significant potential for plastic waste upcycling and environmental sustainability.