Manipulating d-orbital of Cu single atom site by coordination engineering for selective oxidation of benzene
Shuchun Li, Changsheng Cao, Jiabin Chen, Wen Wen, Xuefei Zhang, Longji Cui, Yuke Li, Xing Huang, Yu Tang, Zailai Xie
Abstract
Single-atom catalysts (SACs) enable atomic-level control over active sites, but orbital-level manipulation to steer catalytic behavior remains challenging. Here, we address this issue through d-orbital engineering of Cu SACs, achieving simultaneous control over coordination geometry (Cu-N3) and high metal loading (33.2 wt%) for direct benzene-to-phenol oxidation with H2O2. The tri-coordinated Cu SAC (Cu-N3-33.2) exhibits the highest performance with 85.8% benzene conversion and a turnover frequency of 680.3 h−1 at 60 oC, ranking it among the best metal-based catalysts. In-situ ATR-IR spectroscopy and DFT calculations reveal that dynamically formed Cu-O intermediates, driven by p-d orbital hybridization between Cu (d orbitals) and O (p orbitals), lower the H2O2 activation barrier by 0.98 eV compared to Cu-N4 sites. High-density atomic Cu sites prevent over-oxidation by consuming singlet oxygen (1O2). This work establishes a dual-parameter optimization paradigm, including orbital configuration and site density, redefining design principles for selective oxidation SACs. Single-atom catalysts provide atomic-level control over active sites but often lack orbital-level manipulation. Here the authors demonstrate orbital engineering of a Cu catalyst, achieving control over coordination geometry and high metal loading.