Fig. 3. Enhanced extracellular photoelectron transport and hydrogen production in surface-conductive algal cells.

a Schematic illustration of the PPy shell-mediated capture and translocation of artificially generated extracellular electrons for enhanced hydrogen production (paired cyan circles) in surface-coated algal cells under air; molecular graphics for EY, TEOA and ascorbate are shown. b, c Histogram (b) of measured surface current for native Chlorella cells with the corresponding value-distribution image (c). d, e Histogram (d) of measured surface current for PPy-coated Chlorella cells with the corresponding value-distribution image (e). The single peak fitting is performed using a Gaussian curve in the histograms. f Time-dependent measurements of hydrogen production for PPy/CaCO₃-coated Chlorella cells with or without EY and TEOA. EY and TEOA are added at the time point of 1 d. Samples are cultivated in seal vials with sodium ascorbate-containing TAP culture medium and exposed to daylight with an intensity of 65 μE m⁻² s⁻¹. Data are presented as mean values ± SD, error bars indicate standard deviations (n = 3, biologically independent samples). All relevant experiments were performed independently at least three times with similar results. Source data are provided as a Source Data file.