Folic acid self-assembly-assisted ultrafine Ru nanoparticles on highly graphitic N-doped carbon for co-electrolytic H2 generation paired with hydrazine oxidation

Overall water splitting (OWS) for H 2 production is limited by the sluggish kinetics of the oxygen evolution reaction (OER). Using hydrazine oxidation reaction (HzOR) with a low theoretical potential to couple with hydrogen evolution reaction (HER) is expected to achieve highly efficient hydrogen production and greatly reduce energy consumption. Herein, using folic acid and RuCl 3 ·xH 2 O as precursors, Ru/porous N-doped carbon (Ru/PNC) was controllably synthesized through a simple mixing and pyrolysis strategy. Ru/PNC exhibits excellent performance for HER and HzOR in alkaline electrolyte, delivering a low overpotential of 1.56 mV for HER and a low potential of –54.9 mV (vs. RHE) for HzOR at 10 mA cm −2 . Remarkably, in the two-electrode overall hydrazine splitting (OHzS) system, Ru/PNC requires only 0.026 and 0.262 V to achieve 10 and 100 mA cm −2 , respectively, in alkaline condition. Additionally, Ru/PNC shows similar HER, better HzOR and OHzS activities compared with Pt/C in neutral condition. The OHzS system can be driven through home-made direct N 2 H 4 -H 2 O 2 fuel cell (DHHPFC) and commercial solar cell to achieve H 2 yields of 24.1 and 32.6 m L per hour, respectively, exhibiting the energy-saving advantages along with robust practicability. This work provides a facile method to prepare the advanced HER and HzOR bifunctional electrocatalysts using folic acid, achieving energy-saving hydrogen production.