A high-throughput screening framework identifies Z-scheme MXene heterojunctions approaching 80% solar-to-hydrogen efficiency

Abstract

In the field of photocatalytic water splitting, Z-scheme heterojunctions exhibit more efficient carrier migration and better photocatalytic performance than single-component materials or Type II heterojunctions. However, their complex design principles have hindered rapid materials discovery. In this work, we constructed 20 800 heterostructures by combining 16 MXene materials with 1300 other two-dimensional (2D) materials. By establishing a high-throughput screening framework based on sequential filtering criteria including staggered band alignment, lattice mismatch (<5%), and built-in electric field direction, we rapidly identified four promising Z-scheme van der Waals heterojunctions: As/Sc2CBr2, MoS2/Ti2CO2, SeTeW/Zr2CO2, and Zr3N2O2/Hf2CO2. Subsequent validation using the HSE06 hybrid functional and ab initio molecular dynamics simulations confirmed their Z-scheme nature. All four heterojunctions possess suitable band edge positions for overall water splitting, excellent optical absorption, and good thermodynamic stability. Among them, Zr3N2O2/Hf2CO2 exhibits an exceptionally high optical absorption coefficient of 3 × 105 cm−1 in the visible-light range. Under ideal conditions assuming 100% internal quantum efficiency, its theoretical solar-to-hydrogen efficiency reaches 77.86%, significantly outperforming most reported Z-scheme systems. Our work provides both a set of high-performance candidate photocatalysts and a generalizable high-throughput framework for efficient discovery of Z-scheme heterojunctions.