title: Photocatalytic oxygen evolution from low-bandgap conjugated microporous polymer nanosheets: a combined first-principles calculation and experimental study.
abstract: Nanostructured semiconducting polymers have emerged as a very promising class of metal-free photocatalytic materials for solar water splitting. However, they generally exhibit low efficiency and lack the ability to utilize long-wavelength photons in a photocatalytic oxygen evolution reaction (OER). Here, based on first-principles calculations, we reveal that the two-dimensional (2D) aza-fused conjugated microporous polymer (aza-CMP) with a honeycomb network is a semiconductor with novel layer-dependent electronic properties. The bandgap of the as-synthesized aza-CMP nanosheets is measured to be 1.22 eV, suggesting that they can effectively boost light absorption in the visible and near infrared (NIR) region. More importantly, aza-CMP also possesses a valence band margin suitable for a photocatalytic OER. Taking advantage of the 2D layered nanostructure, we further show that the exfoliated ultrathin aza-CMP nanosheets can exhibit a three-fold enhancement in the photocatalytic OER. After deposition of a Co(OH)2cocatalyst, the hybrid Co(OH)2/aza-CMP photocatalyst exhibits a markedly improved performance for photocatalytic O2evolution. Furthermore, first-principles calculations reveal that the photocatalytic O2evolution reaction is energetically feasible for aza-CMP nanosheets under visible light irradiation. Our findings reveal that nanostructured polymers hold great potential for photocatalytic applications with efficient solar energy utilization.
authors.affiliation: Department of Polymer Science and Engineering, CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China. hxu@ustc.edu.cn.
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.affiliation: CAS Key Laboratory of Materials for Energy Conversion, Hefei National Laboratory of Physical Sciences at the Microscale, CAS Center for Excellence in Nanoscience, School of Chemistry and Materials Sciences, and Synergetic Innovation of Quantum Information & Quantum Technology, University of Science and Technology of China, Hefei, Anhui 230026, China. xjwu@ustc.edu.cn.
authors.forename: Yangyang
authors.initials: Y
authors.lastname: Wan
authors.affiliation: Department of Polymer Science and Engineering, CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China. hxu@ustc.edu.cn.
authors.forename: Yanjun
authors.initials: Y
authors.lastname: Ding
authors.affiliation: Department of Polymer Science and Engineering, CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China. hxu@ustc.edu.cn.
authors.forename: Yuchen
authors.initials: Y
authors.lastname: Niu
authors.affiliation: Department of Chemistry, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Yujie
authors.identifier: http://orcid.org/0000-0002-1995-8257
authors.initials: Y
authors.lastname: Xiong
authors.affiliation: CAS Key Laboratory of Materials for Energy Conversion, Hefei National Laboratory of Physical Sciences at the Microscale, CAS Center for Excellence in Nanoscience, School of Chemistry and Materials Sciences, and Synergetic Innovation of Quantum Information & Quantum Technology, University of Science and Technology of China, Hefei, Anhui 230026, China. xjwu@ustc.edu.cn.
authors.forename: Xiaojun
authors.identifier: http://orcid.org/0000-0003-3606-1211
authors.initials: X
authors.lastname: Wu
authors.affiliation: Department of Polymer Science and Engineering, CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China. hxu@ustc.edu.cn.
authors.forename: Hangxun
authors.identifier: http://orcid.org/0000-0003-1645-9003
authors.initials: H
authors.lastname: Xu