Mechanochemical engineering of interfacial charge-transfer architectures for pollutant degradation, carbon capture, and hydrogen generation

Abstract Mechanochemical ball milling has progressed beyond a solvent-free synthesis route into a precision strategy for programming interfacial charge-transfer architectures in photocatalytic systems. This review critically examines how ball-milling-induced solid–solid interactions regulate charge separation, redox retention, and electron utilization across heterojunctions employed in pollutant degradation, hydrogen evolution, and CO 2 reduction. Rather than cataloging material combinations, this mini review centers on how mechanochemistry stabilizes distinct charge-transfer topologies, including Type II polymer heterojunctions, Z- and S-scheme systems, Schottky contacts, and ohmic interfaces, through enforced electronic coherence, defect–interface coupling, and Fermi-level equilibration. Quantitative comparisons reveal that catalytic performance scales with interface-governed charge regulation rather than compositional complexity, with ball-milled systems achieving hydrogen evolution rates exceeding 10 3 –10 4 μ mol g −1 h −1 and near-complete pollutant removal under visible light. By integrating kinetic data, spectroscopic evidence, and theoretical insights, this review establishes mechanochemical ball milling as a charge-architecture engineering tool capable of deterministically shaping photocatalytic function. Remaining challenges related to scalability, defect stability, and real-matrix performance are discussed to delineate pathways toward industrially relevant, interface-programmed photocatalysis.