Dual-ligand engineering of Ti-Based MOFs for efficient piezo-photocatalytic overall water splitting

Abstract

Driven by the global goal of carbon neutrality, solar-driven photocatalytic overall water splitting provides a critical pathway for directly converting light energy into storable green hydrogen. However, solar to hydrogen efficiency is often limited by the slow kinetics of charge carrier separation, migration, and surface reactions. Although MOF/inorganic semiconductor heterojunctions can promote carrier separation by establishing built-in electric fields, dense inorganic phases often block MOF pores and shield active sites, thereby compromising the structural advantages of MOFs. Herein, we propose a dual-ligand engineering strategy to regulate the electronic structure and piezo-photocatalytic behavior of titanium-based MOFs, achieving efficient piezo-photocatalytic overall water splitting. By co-coordinating terephthalic acid and 2-aminoterephthalic acid with titanium precursors, the as-synthesized material preserves the high specific surface area of MOFs while introducing amino-functionalized linkers into the framework. The incorporation of amino ligands breaks the centrosymmetry of the material and endows the dual-ligand MOF with piezoelectricity. Under the synergistic excitation of light and ultrasound, carrier recombination is significantly suppressed and charge transfer within the framework is accelerated, enabling efficient and stable overall water splitting without sacrificial agents. This study provides a feasible dual-ligand modulation strategy for improving MOF-based piezo-photocatalytic overall water splitting and elucidates the synergistic regulation mechanism of charge dynamics and surface reaction kinetics under multi-field coupling.