RuNi heterojunction alloy decorated cellulose filter as binder-free high-efficiency electrocatalyst for water splitting

In light of the resplendent prospect of water electrolysis, the development of cost-effective, robust and efficient hydrogen/oxygen evolution reactions (HER/OER) bifunctional electrocatalysts is a major challenging task. Herein, RuNi heterojunction alloy decorated cellulose filter (RuNi/CF) as bifunctional electrocatalysts for OER and HER to boost water splitting was successfully synthesized through a two-step of electroless plating and electrodeposition. Benefiting from the unique structure and well-designed electronic engineering of RuNi alloy decorated on cellulose filter, RuNi/CF exhibits outstanding performance for water splitting as a bifunctional electrocatalyst. Density functional theory (DFT) calculation proves that the introduction of Ru makes the electrons around Ni rearrange, which in turn changes the density of the electron cloud around Ni. In alkaline media, the as-prepared Ru 10 Ni/CF displays a very low overpotential of 370 mV to deliver 100 mA/cm 2 with the corresponding Tafel slope of 149 mV/dec for OER. Moreover, it required a small overpotential of 64 mV to carry out a current density of 10 mA/cm 2 for HER. As a result, the assembled water splitting electrolyzer with the Ru 10 Ni/CF shows a very low voltage of 1.56 V to reach 10 mA/cm 2 at alkaline conditions. The cellulose-based self-supporting electrode exhibits abundant HER and OER highly active sites and a robust 3D network structure, especially the electronic structure adjustment from the accumulation of bimetals, which together promote electron transport, resulting in excellent catalytic activity and durability in water splitting. The work may provide insights for the innovative strategy of noble metal electrocatalysts for water splitting.