The synthesis of photocatalysts with both broad light absorption and efficient charge separation is significant for a high solar energy conversion, which still remains to be a challenge.

The gap

Consensus across the literature

Supporting evidence — 3 representative gaps

• Donor-acceptor conjugated polymers for the photosynthesis of H2O2 in pure water (2026) · doi

  The photocatalytic synthesis of H2O2 has emerged as a promising sustainable strategy to replace the traditional anthraquinone process. D-A conjugated polymers, owing to their tunable band structures, broad visible-light absorption, and efficient charge separation, have demon- strated remarkable potential as photocatalysts for sacri- ficial-agent-free H2O2 production in pure water. Recent progress has highlighted the importance of rational molecular engineering, including modulation of donor and acceptor units, linkage design, topology optimiza- tion, active-site regulation, and mass transfer enhance- ment. These strategies have significantly improved the production rate, selectivity, and stability of D-A conju- gated polymers for H2O2 photosynthesis, pushing the field closer toward practical applications. Despite these advances, several challenges remain. First, the solar-to-chemical conversion efficiency is still limited under ambient conditions. Currently, the reported solar-to-chemical conversion efficiency is still not higher than 3%, which is far from the industrial requirement for the photoproduction of H2O2. Addition- ally, stability during long-term operation requires further improvement. Apparent decay can be observed for many reported D-A conjugated polymers after several cycling tests, which could be attributed to the change in the chemical structure of the photocatalysts during opera- tion. Second, the structure-activity relationship is still lacking. Until now, the exploration of the D-A conjugated polymers employs a “trial and error” method, which is comparatively low efficiency. Therefore, the structure- activity relationship is highly needed for the directed design of the photocatalysts. In addition, stability dur- ing long-term operation remains another critical chal- lenge. Significant performance decay has been observed for many reported photocatalysts after repeated cycling tests, which may originate from changes in the chemical Wang et al. Catal (2026) 2:13 Page 14 of 18 Fig. 11 a The behaviors of excitons, polarons and charge carriers in 3D photocatalysts with much enhanced mass transfer comparing to 2D photocata- lysts [78]. Copyright 2024, Springer Nature. b 2D covalent organic framework with engineered hydraulically active 1D channels [47]. Copyright 2024,

  Keywords: photocatalysts polymers chemical conjugated stability efficiency still reported structure charge production design tion active mass
• Anisotropic Charge Migration on Perovskite Oxysulfide for Boosting Photocatalytic Overall Water Splitting (2024) · doi

  The synthesis of photocatalysts with both broad light absorption and efficient charge separation is significant for a high solar energy conversion, which still remains to be a challenge.

  Keywords: synthesis photocatalysts broad light absorption efficient charge separation significant high solar energy conversion still remains
• A A Short Review of Recent Advances in ArtificialP hotosynthesis Chemistry (2026) · doi

  Recent advances in artificial photosynthesis have im- proved catalyst performance and integrated system effi- ciencies, bringing laboratory prototypes closer to practi- cal applications. Future research should explicitly target the development of durable, earth-abundant catalysts, design optimized multi-component interfaces for efficient light harvesting and charge transfer, scalable fabrica- tion of device architectures, and mechanistic studies combining experimental and computational approaches. Focusing on these areas (Scalable Synthesis, Device Integration, Product Selectivity) will accelerate the development of sustainable, high-efficiency artificial pho- tosynthetic technologies. 8. CONCLUSIONS In the last three to five years (2020–2025), chemical re- search in artificial photosynthesis has achieved meaning- ful advances in both catalyst design and integrated sys- tems. Researchers have developed self-photosensitizing molecular catalysts and robust hybrid assemblies that improve light absorption and charge transfer, while new earth-abundant catalysts show enhanced activity and se- lectivity for CO2 reduction and water oxidation. Progress in artificial leaf architectures and photoelectrochemical cells has also demonstrated higher solar-to-chemical conversion efficiencies under practical conditions, nar- rowing the gap between fundamental chemistry and func- tional prototypes. Despite remaining challenges in long- term stability, material cost, and scale-up, recent studies highlight promising strategies such as bio-inspired cata- lyst motifs, optimized ligand environments, and coupled catalytic interfaces. Key takeaways from this review: • Main progress: Self-photosensitizing molecular cat- alysts (Ru and Co) eliminate the need for separate photosensitizers, simplifying system design. MOF and COF frameworks have improved catalyst stability by 10–20× compared to homogeneous analogs. • Main bottleneck – stability: Most advanced cata- lysts still degrade within 12–100 h of continuous op- eration. Commercial viability requires >1000 h (or >1 year) of stability. © 2026 JAST Sana’a University Journal of Applied Sciences and Technology

  Keywords: artificial stability catalyst catalysts design recent advances photosynthesis integrated system prototypes development earth abundant optimized