Efficient Hydrogen Production from Seawater via Fe-EL-Modified Catalysts: A Biomass-Coupled Approach for Sustainable Energy Storage.

Hydrogen production from seawater electrolysis holds significant promise for future energy crisis. However, various ions in the seawater disrupt the electrolysis process, impelling the discovery of efficient oxygen evolution reaction (OER) catalysts coupling with organic small molecules to accelerate the hydrogen generation efficiency. Herein, an easy method is presented for loading Fe electrodepositon layer (EL) onto carbonized wood (CW) via a straightforward electrodeposition process. Fe-EL enriches the active sites on the hierarchical pores natural carbon materials, resulting in exceptional hydrogen evolution reaction (HER) performance. In KOH and artificial seawater, Fe-CW demonstrates overpotentials of merely 38 and 94 mV at 10 mA cm^-2, accompanied with excellent stability. For the anodic counterpart, OER is replaced with the 5-hydroxyfurfural oxidation reaction (HMFOR) using Fe/NiB/CF catalyst. It achieves an oxidation potential of 1.46 V to attain 100 mA cm^-2 for HMFOR and convertes 5-hydroxyfurfural to 2,5-furandicarboxylic acid with a remarkable conversion rate of approximately 100%. When coupled HER with HMFOR in the seawater, the Fe-CW‖Fe/NiB/CF cell achieves 100 mA cm^-2 at an ultralow voltage of 1.47 V. This approach not only addresses the challenges posed by seawater electrolysis but also paves ways for the industrial application of biomass-coupled hydrogen production.