Abiotic Photo-Electrochemical Synthesis of Enantiopure D-Glucose from CO₂ and H₂O: The D-Chip Concept

Technical Brief
Abiotic Photo-Electrochemical Cascade for Enantiopure D-Glucose from CO₂ + H₂O
(“D-Chip” – Compact Microfluidic Architecture)

License
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
You are free to share and adapt the material for any purpose, including commercial use, provided appropriate credit is given to the author.

1. Primary Goal
Demonstrate a fully abiotic, continuous-flow photo-electrochemical system that converts CO₂ and H₂O into enantiopure (or highly enantioenriched) D-glucose. The system is realized as an ordered catalyst stack inside a quartz microfluidic chip and is intended for space, lunar, planetary, or other closed-loop environments where biological primary production is undesirable or impractical.

2. Why D-Glucose
D-glucose is the preferred carbon and energy substrate for the vast majority of organisms. A reliable abiotic source of enantiopure D-glucose therefore supplies both a high-value nutritional product and a universal feedstock. Once available, existing industrial biotechnology can convert that glucose into essential amino acids, vitamins, and other micronutrients. The downstream micronutrient step is largely an adaptation of prior art; the enabling front-end is the abiotic synthesis of the glucose itself.

3. System Architecture

• Substrate: 20 × 20 mm quartz wafer with ~150 µm serpentine microchannels
• Electrical contacting: Au perimeter busbars
• Catalyst stack (top → bottom):
  1. Graphene quantum dot (GQD) mesh with embedded Au/Ag nanoparticles – photo-activation and initial CO₂ reduction
  2. Nitrogen-doped graphene supporting Cu₄–Cu₈ clusters and single-atom Zn sites – C–C coupling and chain growth
  3. Immobilized Rh-BINAP and Mn-salen coordination sites – stereoselective assembly to D-glucose

Energy input is provided by controlled illumination and, optionally, an applied electrochemical potential.

4. Working Intermediate Cascade
(These are experimental checkpoints only. The project target remains enantiopure D-glucose.)

5. Phased Experimental Plan
Phases exist solely to de-risk the cascade. Ultimate success is defined by production of D-glucose.

• Phase 0 – Single-layer baselines: quantify activity, selectivity, and stability of each layer in isolation.
• Phase 1 – Layer 1 → Layer 2 sequential tests: verify efficient conversion of C₁ products into the C₂/C₃ building blocks required for glucose.
• Phase 2 – Full three-layer microfluidic stack under continuous flow: measure D-glucose formation, enantiomeric excess, carbon selectivity, and multi-day stability.
• Phase 3 (later) – Operation under space-relevant conditions (intermittent power, reduced pressure, impurity tolerance, etc.).

6. Success Metrics

Final system target (Phase 2+)

• Clear production of D-glucose
• Enantiomeric excess ≥50 % (stretch goal ≥80 %)
• Carbon selectivity from CO₂ to D-glucose of at least 5–10 % in initial integrated tests (higher once optimized)
• Stable continuous operation ≥72–100 h with no catastrophic deactivation or significant metal leaching

Intermediate experimental gates (progress tracking only)

• Layer 1: ≥60 % selectivity to *CO or formaldehyde, ≥24 h stability
• Layer 1 + Layer 2: ≥35 % carbon selectivity to glycolaldehyde or glyceraldehyde, ≥48 h stability

7. Key Risks

• Retention of activity and enantioselectivity by the immobilized chiral sites under continuous multi-reactant flow
• Engineering a directional free-energy cascade rather than parallel side reactions
• Suppression of uncontrolled formose-type polymerization
• Achievement of practical overall energy efficiency

8. Downstream Context
Conversion of D-glucose into essential micronutrients is established industrial biotechnology. Once a reliable abiotic supply of enantiopure D-glucose exists, existing microbial or cell-free systems can be adapted for spacecraft, lunar, planetary, or other closed-loop settings. That adaptation work is separate from, and enabled by, successful development of the D-chip.

9. Collaboration / Call for Experimental Evaluation
This concept is released so that groups with the necessary experimental capabilities in photo-electrochemical C O₂ reduction, supported molecular or cluster catalysts, and microfluidic reactors can evaluate and advance it. The author lacks the laboratory resources to execute the phased plan and welcomes independent testing, improvement, or critique.

Contact: r21782818@protonmail.com