Ni@Ni2P Encapsulation in Interconnected N-Doped Carbonized Cellulose Nanofibril Network for Efficient Oxygen Evolution Reaction

Production of cost-efficient and robust electrocatalysts toward oxygen evaluation reaction (OER) is a challenging work. In this work, cellulose nanofibrils (CNF) obtained from natural plant fiber with distinctive three-dimensional networks are used as structural skeletons and conductive substrates for electrocatalytic materials. One-step pyrolysis of aerogel composed of CNF and nickel salt yields Ni@Ni2P nanoparticles encapsulated in nitrogen-doped interconnected carbonized CNF and carbon nanotubes (denoted as Ni@Ni2P/N-CNF-CN). Benefiting from the desirable characteristics conferred by the carbon substrates, such as large specific surface area, multitudinous mesopores, and favorable conductivity, the hybrid catalyst exhibits excellent catalytic performance toward OER with a low overpotential of 269 mV to reach a current density of 10 mA cm(-2) and a low Tafel slope of 65.0 mV dec(-1) in 1 M KOH solution. Furthermore, the as-prepared catalyst also reveals favorable stability with 1.7% decay after 20 h long-term chronopotentiometry testing. The approach to convert inexpensive and renewable biopolymers into high value-added carbon based electrocatalytic materials described in the present work provides novel, green, and broader opportunities for the utilization of biomass materials.