Synergistic Defect Engineering and Self-Assembled Nafion on Photoanodes Enabling Selective Photoelectrochemical Glucose Oxidation Coupled H₂ Production

Traditional photoelectrochemical (PEC) water splitting generally involves the kinetically sluggish oxygen evolution reaction, which not only restricts the hydrogen evolution reaction but also yields oxygen with little economic value. Herein, a Nafion/TiO_2-x photoanode is designed for coupling the PEC glucose oxidation reaction (GOR) with hydrogen production. Benefiting from charge migration between the Nafion layer and TiO_2-x, this approach effectively suppresses non-radiative recombination caused by vacancy-related surface traps. It also induces band bending, thereby enhancing the directional separation of photo-generated charges. Compared to pristine TiO₂, this photoanode exhibits a fivefold increase in photocurrent density, outstanding long-term stability, and an absorbed photon-to-current conversion efficiency of 100%. Furthermore, the glucose oxidation efficiency reaches 97.8%, with a Faradaic efficiency of 80% for the selective oxidation of glucose to the high-value-added product of glucaric acid. Concurrently, the Faradaic efficiency for hydrogen evolution at the cathode is 99%, enabling simultaneous high-value organic synthesis and hydrogen co-production. Moreover, the Nafion/TiO_2-x photoanode demonstrates ultra-low detection limits and linear response at ultra-low concentrations for photoelectrochemical sensing. This research offers novel insights for synergistically optimising biomass resource utilisation and clean energy production.