Advances in Molecular Interfacial Engineering of Heterojunctions for Photocatalytic CO2 Reduction

Abstract

The unsustainable reliance on fossil fuels has triggered an alarming accumulation of atmospheric CO2, exacerbating global energy insecurity and environmental degradation. Photocatalytic CO₂ reduction, an artificial photosynthetic paradigm leveraging solar energy to convert CO₂ into renewable hydrocarbons (e.g., CH4, C2H4, CH3COOH), has emerged as a prominent strategy in green chemistry to reconcile carbon neutrality with sustainable fuel production. This review critically examines interfacial engineering in semiconductor heterojunctions, which governs charge carrier dynamics, active site exposure, and reaction pathways by manipulating interfacial interactions (π-π stacking, Coulombic force, Van der Waals force, hydrogen bond, covalent bond). We articulate the mechanistic synergy between band alignment principles and green chemistry frameworks, emphasizing how interfacial effects orchestrate thermodynamics (e.g., CO₂ activation energy barriers) and kinetics (e.g., C-C coupling rates) to enhance selectivity and quantum efficiency of photocatalytic CO2 reduction. By addressing critical challenges confronting scalable CO₂ valorization, including charge recombination and product specificity limitations, we propose forward-looking perspectives integrating atomic-scale bond modulation, circular material lifecycles, and energy-autonomous photoreactor designs. Establishing conceptual bridges between interfacial science and green process engineering, this work provides a framework to guide the rational design of interfacial interactions, advancing CO₂ transformation from an ecological liability to a cornerstone of circular carbon economies.