Over the past decade, halide perovskites have emerged as a promising class of materials for solar energy conversion and optoelectronic applications, owing to their outstanding optoelectronic properties, low processing costs, and high compositional tunability. Despite these advances, their application in photocatalysis remains strongly limited by poor stability, particularly in aqueous environments or under high-humidity conditions, as well as by environmental and health concerns associated with the toxicity of lead-based compounds. This thesis follows a targeted design strategy for halide perovskite-based composite materials, aiming to enhance their stability while preserving, or even improving, their photocatalytic properties. To this end, heterostructures are developed by combining halide perovskites with various families of functional materials, including carbon-based materials (H-GDY), metal oxides (TiO2), and molecular photosensitizers (eosin Y). This interface engineering aims to enhance perovskite stability against moisture and aqueous media, while promoting interfacial charge carrier transfer, limiting recombination, and consequently improving the photocatalytic efficiency of the developed systems. Furthermore, building on knowledge from lead-based systems, this study explores the development of lead-free halide perovskites as more sustainable, environmentally friendly alternatives. This work emphasizes understanding the relationships among structure, physicochemical properties, and photocatalytic performance. For this purpose, the materials are characterized using a complementary set of structural, spectroscopic, electrochemical, and photophysical techniques, enabling clarification of the mechanisms governing their electronic properties and behavior under irradiation. Finally, the developed materials are applied in various photocatalytic redox reactions, including carbon dioxide reduction, biomass-derived compound valorization, and photocatalytic hydrogen production. The results demonstrate that interface engineering is a particularly effective strategy for enhancing the performance of halide perovskites. This work thus offers new perspectives for the development of efficient, stable, and sustainable photocatalysts for solar energy conversion and valorization technologies.