[FeFe]-H2ase from Clostridium pasteurianum (CpI) and [NiFeSe]-H2ase from Desulfovibrio vulgaris Hildenborough (DvH) were expressed and purified under anaerobic conditions. Figure illustrates the hypothesis that the negatively charged NCN CNX possesses the ability to activate enzymes with positively charged electron entry points, such as CpI [FeFe]-H2ase. Additionally, the unique property of NCN CNX in converting alcohols selectively into aldehydes offers an opportunity to monitor the clean oxidation reaction of 4-methylbenzyl alcohol (4-MBA) to 4methylbenzaldehyde (p-tolualdehyde), allowing the quantification of stoichiometry from the products resulting from oxidation and reduction. To construct a photocatalytic system for solar H2 production coupled with selective alcohol oxidation, we interfaced [FeFe]-H2ase with NCN CNX in the presence of 50 mM 4-MBA in 1 mL aqueous MOPS buffer solution (0.1 M, pH 7). To determine the surface charge of NCN CNX, zeta potential measurements were performed. Notably, the presence of light-induced blue radicals (absorption band from 500-750 nm, Figure ) did not impact the surface charge of NCN CNX (Figure ), indicating that these radicals are long-lived and deeply trapped photoelectrons. The negatively charged surface is primarily attributed to the cyanamide group, which maintains a negative zeta potential even at a pH below 2 (Figure ). CpI [FeFe]-H2ase was selected due to its distal FeS cluster ([4Fe-4S]) being surrounded by a positively charged region containing surface arginine and lysine residues. In vivo, this distal FeS cluster region is thought to interact with the negatively charged region of ferredoxin for electron transfer. By constructing electrostatic NCN CNX-[FeFe]-H2ase assemblies, we achieve efficient solar H2 production, with NCN CNX mimicking the role of ferredoxin to deliver electrons directly into [FeFe]-H2ase. Time-dependent photocatalytic H2 evolution using NCN CNX-[FeFe]-H2ase complexes is illustrated in Figure . Notably, a nearly linear increase in H2 yield is observed during the initial 4 h, reaching 3.0 ± 0.3 µmol with a TOF of 18,669 h -1 . This TOF value is approximately 4.5 times higher than the previous benchmark (4,117 h -1 ) and is even comparable to systems utilizing MET such as g-C3N4|TiO2 (TOF = 20,000 h -1 ) (note that previous systems used Desulfomicrobium baculatum (Dmb) [NiFeSe]-H2ases). Continuous irradiation of the NCN CNX|[FeFe]-H2ase assemblies for 24 h yielded 7.9 ± 0.6 µmol of H2 (TON = 198,125). The efficient DET between NCN CNX and [FeFe]-H2ase can be attributed to the specific electrostatic interaction at the interface, which will be further evaluated by QCM and PEIS. Furthermore, 4-MBA was selectively oxidized to p-tolualdehyde (Figure ), with a H2:p-tolualdehyde ratio of 0.77. The observed ratio indicates the deep trapping of some photogenerated electrons within the CNX polymeric structure and minor oxidation of MOPS, while the majority of photogenerated holes persist in selectively oxidizing 4-MBA. Exclusion controls were conducted by removing individual components from the photocatalytic system. As depicted in Figure and Figure , the system exhibited significantly reduced efficiency in the absence of any component, with H2 yields below 0.3 µmol over 4 h. Notably, control experiments were also performed to validate the proposed electrostatic interactions using a DvH [NiFeSe]-H2ase, differing from the previously reported Dmb [NiFeSe]-H2ase. The distal FeS cluster of both [NiFeSe]-H2ases near its surface is surrounded by amino acids that lead to a local negative charge, serving as the electron entry point for interaction with the positively charged heme of cytochrome c3 during electron transfer in vivo. Interfacing DvH [NiFeSe]-H2ase with NCN CNX resulted in the production of 8.6 ± 0.33 nmol of H2 in 4 h, with a significantly lower TON of 215 (Figure ). These results indicate that electrostatic repulsion prevents DET in this system. A detailed comparison among stateof-the-art photocatalytic systems combining carbonaceous photocatalysts and H2ase are listed in Table . CDs|[NiFeSe]-H2ase+EDTA 3,125 44,000 [23] CDs|[FeFe]-H2ase+TEOA 1,500 19,000 [11] Photocatalytic system (MET) TOF (h -1 ) TON Ref. CDs|[FeFe]-H2ase+TEOA+MV 2,000 32,000 [11] [a] TOF is calculated from 4 h photocatalysis.