In reality, we do observe some contaminants trapped between the hBN and graphite, which favorably agglomerate in micro/nanoscopic pockets visible in AFM (Fig. ), due to the selfcleaning process occurring at the vdW interfaces. Importantly, the average height of these pockets is at least 5 nm, leading to a negligible overlap between the electron wave functions of the redox mediator and graphite, which therefore only results in a mere reduction of the apparent tunneling area.