Natural photosynthesis stores sunlight in chemical energy carriers, but it has not evolved for the efficient synthesis of fuels, such as H2. Semi-artificial photosynthesis combines the strengths of natural photosynthesis with synthetic chemistry and materials science to develop model systems that overcome Nature’s limitations, such as low-yielding metabolic pathways and non-complementary light absorption by Photosystem (PS) I and II. Here, we report a bias-free semi-artificial tandem platform that wires PSII to hydrogenase for overall water splitting. This photoelectrochemical cell integrated the red and blue light-absorber PSII with a green light-absorbing diketopyrrolopyrrole dye-sensitised TiO2 photoanode enabling complementary panchromatic solar light absorption. Effective electronic communication at the enzyme-material interface was engineered using an Os complex-modified redox polymer on a hierarchically-structured TiO2. This system provides a design protocol for bias-free semi-artificial Z-schemes in vitro and provides an extended toolbox of biotic and abiotic components to re-engineer photosynthetic pathways.