Catalysis in low-dimensional materials

Single-atom catalysts (SACs) emerge as promising alternatives to Pt-based catalysts yet encounter challenges, including limited choices of center metals and low single-atom loading. Transition-metal SACs have captured considerable attention in electrocatalysis due to their remarkable attributes, including optimized atom utilization, flexible coordination structure regulation, and exceptional catalytic selectivity and activity. Typically, these SACs consist of single transition-metal atoms immobilized within a N-doped carbon matrix, coordinated by in-plane C or N atoms.

To enhance catalytic activity, significant efforts have been directed towards understanding how metal-atom centers and in-plane coordinating atoms influence the binding energy of SACs with reaction intermediates. In collaboration with experimental colleagues, we explore various SACs within graphene-like host systems for a range of catalytic reactions, with a particular focus on the oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER). Additionally, we delve into another avenue of low-dimensional materials to enhance catalytic performance. Conjugated polymers, characterized by delocalized π-systems, offer tunable energy levels, atomic-level active site modulation, and facile, cost-effective synthetic routes. Furthermore, their inherent ambipolarity, allowing the transport of both electrons and holes, positions them as excellent candidates for achieving overall water splitting with a single electrode, thereby reducing costs and simplifying cell design.

To date, no organic or inorganic photoelectrodes have demonstrated simultaneous hydrogen and oxygen production due to stringent thermodynamic requirements. This necessitates conduction band (CB) and valence band (VB) positions above the HER level and below the OER level, respectively, along with ambipolarity, appropriate bandgaps, and active sites for both half-reactions. In collaboration with experimental partners, we investigated novel conjugated acetylenic polymers (CAPs) as a material able to act as both photoanode and photocathode.

Publications:

M. Borrelli, Y. An, C. J. Querebillo, A. Morag, C. Neumann, A. Turchanin, H. Sun, A. Kuc, I. M. Weidinger, X. Feng, Donor-Acceptor Conjugated Acetylenic Polymers for High-Performance Bifunctional Photoelectrodes, ChemSusChem e202301170 (2023), DOI: https://doi.org/10.1002/cssc.202301170.
X. Wang, Y. An, L. Liu, L. Fang, Y. Liu, J. Zhang, H. Qi, T. Heine, T. Li, A. Kuc, M. Yu, X. Feng, Atomically Dispersed Pentacoordinated-Zirconium Catalyst with Axial Oxygen Ligand for Oxygen Reduction Reaction, Angew. Chem. Int. Ed. 61, e202209746 (2022), DOI: https://doi.org/10.1002/anie.202209746.
G. Chen, Y. An, S. Liu, F. Sun, H. Qi, H. Wu, Y. He, P. Liu, R. Shi, J. Zhang, A. Kuc, U. Kaiser, T. Zhang, T. Heine, G. Wu, X. Feng, Highly accessible and dense surface single metal FeN4 active sites for promoting the oxygen reduction reaction, Energy Environ. Sci. 15, 2619 (2022), DOI: https://doi.org/10.1039/d2ee00542e.