Universal electronic descriptors for optimizing hydrogen evolution in transition metal-doped MXenes

The integration of transition metal (TM) atoms into two-dimensional (2D) transition metal carbides and nitrides (MXenes) has been identified as a promising strategy for enhancing hydrogen evolution reaction (HER) performance. However, the vast combinatorial space presents challenges for rapid catalyst screening. In response, high-throughput calculations were conducted on Ti2CO2 and Zr2CO2 doped with a wide array of TM single atoms. The local structural and corresponding electronic structural changes were analyzed, with an emphasis on their implications for HER performance. Furthermore, universal electronic descriptors were developed using the Sure Independence Screening and Sparsifying Operator (SISSO) method, harmonizing the Gibbs free energy of hydrogen adsorption (Delta GH*) trends across different MXenes substrates doped with TM atoms. These descriptors enabled the prediction of Cr, Fe, Ru, Pd, Os, and Ir as effective dopants for optimizing the Delta GH* of Hf2CO2, resulting in a reduction of Delta GH* from 1.082 eV to within +/- 0.2 eV. Our work not only highlights the potential of these TM dopants in significantly enhancing the catalytic activity of MXenes but also underscores the value of universal electronic structure descriptors in rapidly identifying and developing high-performance HER catalysts.