Ruthenium nanoparticles modified oxidized, N-doped carbon substrates: Hydrogen generation electrocatalysts in alkaline and acidic conditions

Various Ru nanoparticles modified porous carbon substrates were prepared as hydrogen evolution electrocatalysts via chemical reduction in this work. Before obtaining the Ru-based catalysts, different carbon substrates, including lignin, straw and shaddock peel, were selected. The carbon substrates were oxidized and nitrogen-doped under ammonia gas to further increase the physicochemical properties. Then, the nitrogen doped lignin, straw and shaddock peel were used as substrates to fabricate various Ru-based composites, which were denoted as Ru@o-NL, Ru@o-NS and Ru@o-NSP. The HER performances of Ru@o-NL, Ru@o-NS and Ru@o-NSP were fully investigated in both acidic and alkaline conditions. Experimental results indicated that all the Ru-based composites could catalyze the hydrogen evolution reaction. Ru@o-NL showed better HER activity than that of the Ru@o-NS and Ru@o-NSP. The dosage of Ru could affect the HER activity. The Ru@o-NL with 8.0 wt% Ru loading has the best HER performance. The overpotentials (@ 10 mA cm−2) of the Ru@o-NL in 0.5 M H2SO4 and 1.0 M KOH were 42 and 14 mV, respectively. The corresponding Tafel slopes were 32 and 59 mV dec−1. It also had large exchange current density and good long term stability.