Volume 41, Issue 8

Hydrogen is a key energy carrier for decarbonizing high-emission sectors, supporting the transition to a sustainable energy future. This review evaluates critical hydrogen storage and transportation technologies essential for a hydrogen-powered economy. Storage methods, including compressed gas (350–700 bar), cryogenic liquid (−253 °C), cryo-compressed (−233 °C, 250–350 bar), material-based approaches (e.g., metal hydrides, LOHCs), and underground storage (salt caverns, aquifers), are analyzed for their technical feasibility, energy efficiency, and scalability. Transportation methods, including pipelines (up to 6,000 km), truck/rail (200–700 bar), and maritime shipping (e.g., liquefied hydrogen, ammonia, and LOHCs), are evaluated, with an emphasis on infrastructure requirements and cost optimization. The study emphasizes advancements in integrating green hydrogen with renewable energy, addressing safety concerns (e.g., hydrogen embrittlement, ammonia toxicity, and leakage risks), and technical challenges (e.g., boil-off losses and material durability), to support global decarbonization objectives.

Photocatalytic hydrogen production is a key pathway toward sustainable energy, driven by semiconductors that utilize sunlight for water splitting. This review highlights recent advances in material design, theoretical modeling, and data-driven discovery. Focus is given to visible-light-active semiconductors with optimal band gaps (1.8–2.4 eV), such as BiVO 4 , g-C 3 N 4 , and CdS, which enable efficient redox reactions. Hybrid architectures, including Pt-loaded TiO 2 and CdS/ZnS core–shell systems, demonstrate hydrogen evolution rates exceeding 10 5  mol m −2  s −1 . Upconversion nanomaterials based on rare-earth-doped fluorides extend light harvesting into the NIR, enhancing quantum yields when combined with quantum dots. Engineered heterojunctions and carbon-based 2D interfaces improve charge separation and suppress recombination. Thermodynamic parameters such as low overpotentials (<0.3 V) and high absorption coefficients (>10 5  cm −1 ) correlate with high catalytic efficiency. Time-dependent simulations and density functional theory (DFT) offer insights into structure–property relationships. Additionally, machine learning models expedite discovery by navigating complex compositional and structural spaces. While integrating theoretical, experimental, and AI-driven approaches, this review presents a framework for the rational design of scalable photocatalysts that meet future energy demands.

The introduction of SAPO-34/ZSM-5 composite zeolites has significantly advanced the field of catalysis due to their unique hierarchical structure, adjustable acidity, and shape-selective properties. By combining the distinct features of ZSM-5 and SAPO-34, these composites have improved catalytic activity, stability, and selectivity in processes such as methanol-to-olefins (MTO). Since 2010, various synthesis techniques, including hydrothermal, ultrasonic-assisted, steam-assisted, microwave assisted, and solid-solid transformation methods, have been developed to optimize the textural and chemical properties of these materials. This review aims to comprehensively examine these synthesis methods, focusing on their conditions, impact on physicochemical properties, and catalytic efficiency. By highlighting recent advancements and addressing existing challenges, we hope to provide insights that will improve composite synthesis and encourage broader industrial applications in catalysis.