Insights into hierarchical porous titanium(iv) phosphonates: synthesis, structure & applications

Abstract

Hierarchically porous titanium(IV) phosphonates (HPTPs) have recently attracted significant attention as a novel class of hybrid materials that achieve remarkable flexibility in structural porosity, chemical strength, and multifunctionality, offering broad applicability compared to traditional hybrid materials. Unlike carboxylate-based metal–organic frameworks (MOFs), they exhibit robust hydrolytic stability due to their multimodal coordinating ability and strong Ti–O–P bonding. This makes them suitable candidates for catalysis, pollutant adsorption, ion exchange, and energy storage. However, despite their promising capabilities, the unpredictable self-assembly of Ti(IV) metal nodes, poor structural crystallinity, and challenges in hierarchical pore size control hinder the tunability of these materials for targeted applications. Furthermore, the relationships between porosity, stability, and catalytic efficiency necessitate further research to improve overall performance. This review critically examines synthetic methodologies, structural features, and emerging applications of HPTPs, highlighting strategies to address these limitations. Despite advancements in synthetic procedures, the crystallization of HPTPs with precise pore topology and desirable electronic characteristics remains challenging. The combination of computational modeling and machine learning may enhance material design, stability, and porosity. Additionally, solventless strategies alongside green fabrication and nanomaterial integration, could further expand the potential applications of HPTPs in energy storage, photocatalysis, and wastewater treatment, paving the way for industrial-scale utilization.