Towards sustainable H2 evolution by using an algal-electro-photosynthetic process: The mediator selection alternates the electron sources for Chlorella sorokiniana SU-1

摘要

? 2023 Hydrogen Energy Publications LLCChlorella sorokiniana SU-1 is employed on the graphite-felt anode of a two-chamber cell connecting potentiostat (+0.4 V vs Ag/AgCl) to study its photoelectrochemical characteristics. Among the mediators selected, the current significantly reached 1.5 mA and 4.0 mA, respectively, when 0.3 mM 2,6-dimethoxy-1,4-benzoquinone and 5.5 mM ferricyanide were spiked. To give significant hydrogen evolution, the applied direct-circuit voltage could be reduced from 2.0 to 1.3 V (producing 1.5 mL-H2 h?1) due to the assistance of the algae-attached anode and platinum-mesh cathode. The current was boosted by spiking 0.2 g L?1 glucose under light/dark conditions. When using ferricyanide as a mediator, the current oscillated under alternating light-on/off conditions, while for 2,6-dimethoxy-1,4-benzoquinone, the increase or decrease of the current was clearly responding to the light going on and off. The microscopic observation of the SU-1 cell attachment indicates successful development by offering adequate illumination and electrode surfaces.