1. Core Principles
Photochemical reactors harness light energy to drive chemical reactions, enabling precise control over reaction pathways and product selectivity. The process involves three key steps:

• Light Absorption: Reactants absorb photons (UV/visible light) to excite electrons from ground to higher energy states.

• Excited-State Reactions: Activated molecules undergo bond cleavage, rearrangement, or coupling, facilitated by catalysts (e.g., TiO₂, ZnO) or direct photolysis.

• Product Formation: Stable molecules are generated through energy dissipation via fluorescence, heat, or further chemical transformations.

2. Technical Advancements
Modern reactors leverage innovative designs to maximize efficiency:

• Parallel Light Sources: LED arrays or laser beams ensure uniform illumination, reducing reaction heterogeneity.

• Continuous Flow Systems: Microfluidic platforms enhance mixing, cooling, and scalability, ideal for high-throughput applications.

• Smart Controls: Real-time monitoring of light intensity, temperature, and pressure optimizes reaction kinetics.

3. Versatile Applications
3.1 Pharmaceutical Synthesis: Enabling rapid drug candidate screening and selective modification of complex molecules.
3.2 Environmental Remediation: Photocatalytic degradation of organic pollutants (e.g., wastewater treatment) and CO₂ reduction.
3.3 Materials Science: Fabrication of advanced nanomaterials, quantum dots, and functional polymers.
3.4 Green Energy: Light-driven water splitting for hydrogen production and solar-to-chemical energy conversion.

4. Advantages Over Traditional Methods

• Mild Conditions: Reactions occur at ambient temperature/pressure, reducing energy costs and safety risks.

• High Selectivity: Tunable light wavelengths target specific reactions, minimizing side products.

• Sustainability: Catalyst recyclability and elimination of hazardous reagents align with green chemistry principles.