The global imperative for clean energy solutions has positioned photocatalytic water splitting as a promising pathway for sustainable hydrogen production. This review comprehensively analyzes recent advances in TiO₂-based photocatalytic systems, focusing on materials engineering, water source effects, and scale-up strategies. We recognize the advancements in nanoscale architectural design, the engineered heterojunction of catalysts, and cocatalyst integration, which have significantly enhanced photocatalytic efficiency. Particular emphasis is placed on the crucial role of water chemistry in photocatalytic system performance, analyzing how different water sources—from wastewater to seawater—impact hydrogen evolution rates and system stability. Additionally, the review addresses key challenges in scaling up these systems, including the optimization of reactor design, light distribution, and mass transfer. Recent developments in artificial intelligence-driven materials discovery and process optimization are discussed, along with emerging opportunities in bio-hybrid systems and CO₂ reduction coupling. Through critical analysis, we identify the fundamental challenges and propose strategic research directions for advancing TiO₂-based photocatalytic technology toward practical implementation. This work will provide a comprehensive framework for exploring advanced TiO₂-based composite materials and developing efficient and scalable photocatalytic systems for multifunctional simultaneous hydrogen production.

The global plastic crisis, with over 400 million metric tons produced annually and minimal recycling, demands urgent solutions. Photocatalytic plastic photoreforming offers a dual benefit: converting non-recyclable plastics into hydrogen fuel and valuable chemicals using solar energy under mild conditions. This critical review highlights recent advances in photocatalyst design, including semiconductors, MOF-derived materials, and co-catalyst systems, and explores key insights into plastic degradation mechanisms and reactor configurations. Operational factors such as pH, light intensity, and flow dynamics are discussed for their impact on hydrogen yield and product selectivity. Life cycle and techno-economic assessments reveal current challenges in efficiency, scalability, and cost to illuminate the feasibility of implementing the technology at industrial scale. This study suggests that innovations in catalyst engineering, light management, and system integration provide viable paths forward. With its potential to upcycle plastic waste and contribute to low-carbon hydrogen economies, photoreforming represents a promising approach in advancing circular economy goals, especially when coupled with policy support and smart separation strategies.

The global imperative for clean energy solutions has positioned photocatalytic water splitting as a promising pathway for sustainable hydrogen production. This review comprehensively analyzes recent advances in TiO2-based photocatalytic systems, focusing on materials engineering, water source effects, and scale-up strategies. We recognize the advancement in nanoscale architectural design, engineered heterojunction of the catalyst, and cocatalyst integration that have significantly enhanced photocatalytic efficiency. Particular emphasis is placed on the crucial role of water chemistry in photocatalytic system performance, analyzing how different water sources—from wastewater to seawater—impact hydrogen evolution rates and system stability. Additionally, the review addresses key challenges in scaling up these systems, including optimization of reactor design, light distribution, and mass transfer. Recent developments in artificial intelligence-driven materials discovery and process optimization are discussed, along with emerging opportunities in bio-hybrid systems and CO2 reduction coupling. Through critical analysis, we identify fundamental challenges and propose strategic research directions for advancing TiO2-based photocatalytic technology toward practical implementation. This work will provide a comprehensive framework for researchers to explore advanced TiO2-based composite materials to develop efficient and scalable photocatalytic systems for multifunctional simultaneous hydrogen production.

Photo-reforming waste polyethylene terephthalate (PET) in alkaline aqueous solutions is a novel approach for green hydrogen production. This study focuses on improving the catalytic efficiency of Pt/TiO₂ for the photo-reforming of waste PET using an innovative dark deposition method to deposit Pt single atoms on nano TiO₂ (Pt/TiO₂), thereby increasing the catalytic efficiency while reducing the cost of the catalyst. The precursor concentration was optimized to control the size and distribution of the Pt clusters/atoms, and the TiO₂ support was annealed at different temperatures to modify the properties of Pt/TiO₂. Nine Pt/TiO₂ catalysts were synthesized using different Pt precursor concentrations and annealing temperatures. The catalysts were characterized to measure their morphological, crystalline, and electronic properties, as well as their hydrogen yields via PET photo-reforming. The hydrogen conversion efficiency and external quantum yield (EQY) were calculated and compared with those of traditional direct-deposited catalysts. The correlation between the different characteristics of the dark-deposited and direct-deposited catalysts and their influence on the hydrogen yield in the photo-reforming process was statistically analyzed using principal component analysis. Catalysts deposited under dark conditions exhibited 5-fold and 7-fold enhancements in hydrogen conversion efficiency and EQY, respectively, compared to conventional catalytic systems. These findings indicate that the proposed catalytic system provides a viable solution for minimizing Pt loading, reducing the cost of the catalyst, and maintaining a higher hydrogen conversion efficiency.

Photo-reforming waste polyethylene terephthalate (PET) in alkaline aqueous solutions provides a novel approach for green hydrogen production. This study focuses on improving the catalytic efficiency of Pt/TiO2 for photo-reforming waste PET with an innovative dark deposition method to deposit Pt single atoms on nano TiO2 (Pt/TiO2), increasing the catalytic efficiency while reducing the cost of the catalyst. The precursor concentration was optimized to control the size and distribution of the Pt clusters/atoms, and the TiO2 support was annealed at different temperatures to modify the properties of Pt/TiO2. Nine Pt/TiO2 catalysts were synthesized using different Pt precursor concentrations and annealing temperatures. The catalysts were characterized to measure their morphological, crystalline, and electronic properties, as well as their hydrogen yields via PET photo-reforming. The hydrogen conversion efficiency and external quantum yield (EQY) were calculated and compared with those of traditional direct-deposited catalysts. The correlation between the different characteristics of the dark-deposited and direct-deposited catalysts and their influence on the hydrogen yield in the photo-reforming process was statistically analyzed using principal component analysis. Catalysts deposited under dark conditions exhibited 5-fold and 7-fold enhancements in hydrogen conversion efficiency and EQY, respectively, compared to conventional catalytic systems. These findings indicate that the proposed catalytic system provides a viable solution to minimize the Pt loading while reducing the cost of the catalyst and maintaining a higher hydrogen conversion efficiency.