Beyond sunlight: A molecular “bridge” protects metals from rust, day and night
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Electronic structure analysis and the corresponding photocathodic protection mechanism of the heterojunction.
view moreCredit: HIGHER EDUCATION PRESS
Despite its potential for marine corrosion control, photocathodic protection (PCP) suffers from a persistent bottleneck: the conflict between thermodynamic driving forces and charge kinetics. While WO3/TiO2 type-II heterojunctions facilitate energy storage, they typically sacrifice reduction potential and face sluggish transport due to surface defects. To date, it has remained a significant challenge to develop a molecular approach that resolves this impasse by simultaneously amplifying the driving force and accelerating kinetics through defect passivation.
Here, we propose a “hydrogen-bond-mediated molecular bridge” strategy by introducing flexible polyvinylpyrrolidone (PVP) into the WO3/TiO2 interface. We demonstrate that PVP carbonyl groups preferentially hydrogen-bond with bridging hydroxyls on TiO2. This interaction not only passivates surface defects but also induces an interfacial dipole field. The resulting electrostatic field shifts the conduction band edge (−0.88 V), amplifying the driving force for electron injection while preserving efficient charge transfer.
This work provides a generalizable paradigm for utilizing soluble polymers to tune inorganic interfaces and achieves “round-the-clock” protection, maintaining a protective potential for over 12 h in darkness. The work entitled “Interfacial hydrogen-bond engineering of PVP–bridged WO3/TiO2 for efficient solar-driven cathodic metal protection” was published in Advanced Powder Materials (Available online on 17 February 2026).
Journal
Advanced Powder Materials
Method of Research
Experimental study
Subject of Research
Not applicable
Article Title
Interfacial hydrogen-bond engineering of PVP–bridged WO3/TiO2 for efficient solar-driven cathodic metal protection
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