Converting solar energy into clean chemical fuels, such as molecular hydrogen (H2), holds promise for advancing the concept of a circular economy. Among various photocatalysts, carbon nitride (CNX) has emerged as a particularly attractive candidate due to its unique advantages, including visible light absorption, cost-effective fabrication, scalability, and low toxicity. To further enhance the photocatalytic performance of CNX, significant efforts have been devoted to chemical modifications and the incorporation of co-catalysts. The introduction of ionic cyanamide functional groups into CNX ( NCN CNX) has demonstrated remarkable improvements in charge separation and photocatalytic activity, attributed to the prolonged lifetimes of photogenerated electrons. Moreover, the negatively charged cyanamide group provides a versatile platform for potential electrostatic interactions with co-catalysts. Nature has evolved enzymes as highly specific biological catalysts to facilitate essential biological processes in living organisms. Among these enzymes, hydrogenases (H2ases) stand out for their remarkable ability to catalyze the interconversion of protons and H2 with exceptional efficiency and near-zero overpotential under mild conditions, surpassing the capabilities of synthetic catalysts. H2ases can be classified into three main types based on their metal cofactors: [NiFe]-H2ase, [FeFe]-H2ase, and [Fe]-H2ase, with [FeFe]-H2ase being generally the most active for the hydrogen evolution reaction (HER). The extensive investigation of H2ases as model biocatalysts has not only inspired the design of artificial mimic systems, but also paves the way for developing biohybrid assemblies in semi-artificial photosynthesis systems. By interfacing CNX with H2ase, we combine the strengths of both artificial and biological approaches, resulting in unique properties that neither system can achieve individually. This integration opens up new avenues for exploring synergistic effects and unlocking unprecedented possibilities in solar energy conversion and catalysis. The activation of [FeFe]-H2ase by light can be considered as a model for the development of efficient bio-hybrid systems. However, such a photocatalytic system has thus far only been demonstrated using either toxic and expensive CdTe nanocrystals or carbon dots with a low turnover number (TON) of 20,000 over 24 h. Direct electron transfer (DET) between graphitic carbon nitride (g-C3N4) and [NiFeSe]-H2ase has been established with non-specific interactions, resulting in a low turnover frequency (TOF) of 4,117 h -1 over 4 h. Subsequent improvements involved the incorporation of a non-diffusional electron mediator, TiO2, between g-C3N4 and [NiFeSe]-H2ase, leading to an enhanced TON (4 h) of 80,000. In addition to its application in H2ase systems, CNX has predominantly been utilized for the regeneration of NADH in mediated electron transfer (MET) processes involving formate dehydrogenase or alcohol dehydrogenase. In this work, we present a novel approach for biological integration with CNX by demonstrating the first instance of an electrostatic interaction with enzymes. This method establishes a new benchmark for solar H2 production, complemented by comprehensive interfacial characterizations utilizing a quartz crystal microbalance (QCM) and photoelectrochemical impedance spectroscopy (PEIS). Specifically, we coupled negatively charged NCN CNX with H2ases containing different surface charges for in vitro photocatalytic H2 production without an external electron relay. The adsorption process of H2ases on NCN CNX is quantified by QCM, whereas PEIS provides insights into the charge carrier dynamics at the biomaterial interface. The NCN CNX photocatalysts were synthesized using melamine and potassium thiocyanate following previously published methods. Detailed synthesis procedures and characterizations, including scanning electron microscopy (SEM), attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy, fluorescence spectroscopy, and ultraviolet-visible spectroscopy are provided in the supporting information (Figure ).