Hydrophobic and Oleophobic Photocatalytic Coatings for Stones and Cementitious Building Substrates: A Bibliometric Perspective (2010–2025)

Hydrophobic and oleophobic photocatalytic coatings are specialised surface treatments that combine either hydrophobicity or oleophobicity and photocatalytic activity. This combination supports applications such as self-cleaning surfaces, anti-fouling, oil–water separation, air purification, and durability enhancement in construction and other industries. These coatings work by creating a surface with carefully engineered surface energy and roughness that resists wetting by both water and oils, while exposing photocatalytic nanoparticles that activate under light to degrade organics. They are often transparent and durable and are now expanding to cementitious building materials, contributing to sustainable, clean, and resilient infrastructure. The motivation for conducting this bibliometric review arises from the fragmented and interdisciplinary nature of the literature on hydrophobic and oleophobic photocatalytic coatings for construction materials, the rapid growth of research in this field, and the absence of a systematic mapping that integrates publication trends, research hotspots, and practical applications. This review delivers a comprehensive quantitative analysis of publication dynamics, encompassing growth trajectories, global research distribution, and thematic evolution, while uncovering dominant and emerging topics. By mapping established innovations and milestones and exposing critical research barriers, it establishes a knowledge framework that will guide future researchers in advancing hydrophobic and oleophobic photocatalytic coatings for construction materials. Another contribution of this review is its ability to capture both past achievements, such as heritage protection and reduced maintenance of existing structures, and ongoing (as well as future) demands, including sustainability, smart city applications, and multifunctional surface technologies, thereby underscoring its relevance across the full spectrum of the built environment.