Structurally Asymmetric Ni−O−Mn Node in Metal–Organic Layers on Carbon Nitride Support for CO <sub>2</sub> Photoreduction
Chen Guan, Xiaoyang Yue, Yulong Liao, Quanjun Xiang
Abstract
Abstract The Jahn–Teller (J–T) effect‐induced lattice distortion presents an advantageous approach to tailor the electronic structure and CO 2 adsorption properties of catalytic centers, consequently conferring desirable photocatalytic CO 2 reduction activity and selectivity. Nevertheless, achieving precise J–T distortion control over catalytic sites to enhance CO 2 adsorption/activation and target‐product desorption remains a formidable challenge. In this work, we successfully induced J–T lattice distortion in neighboring Ni sites by exchanging high‐spin Mn 2+ into Ni−O−Ni nodes. EXAFS results and DFT simulations revealed that the highly asymmetric Ni−O−Mn nodes induced structural contraction (shortened Ni−O bonds) in the adjacent Ni−O lattice. The magnetic hysteresis loop (M−H) confirmed that the introduction of Mn 2+ increased the number of spin electrons, thereby increasing the magnetization intensity. The spin mismatch between photogenerated electrons and holes suppressed charge recombination. Significantly, the d orbitals of the Ni sites in the Ni−O−Mn nodes exhibited strong orbital hybridization with the p orbitals of CO 2 , as evidenced by the enhanced d‐p orbital overlap, facilitating rapid CO 2 adsorption and activation. Consequently, the sample featuring lattice‐mismatched Ni−O−Mn nodes exhibited an 8.79‐fold enhancement in CO production rate compared to the Ni−O−Ni nodes, in the absence of cocatalysts and sacrificial reagents.