A highly efficient hematite photoelectrochemical fuel cell for solar-driven hydrogen production

Hematite has demonstrated to be a promising photoanode for photoelectrochemical (PEC) hydrogen production because of its narrow band gap and outstanding stability. However, the sluggish water oxidation kinetics on hematite photoanode severely hinder the PEC hydrogen production performance. Herein, we report the construction of a Ti-doped porous hematite-based PEC fuel cell utilizing l-cysteine (L-Cys) oxidation to replace difficult water oxidation for efficient H2 production. The strong complexation interaction between hematite and L-Cys confers the direct photooxidation of L-Cys, producing additional electrons to participate in hydrogen production. As a result, the present Ti-doped porous hematite (Ti-PH) photoanode exhibits a current density of up to 4.45 mA cm−2 at 1.23 V vs. RHE under AM 1.5G illumination. This work provides a new strategy to utilize the additional electron contribution from photoinduced oxidation of organic chemicals for high-efficiency PEC fuel cell and solar fuel production.