3D Sulfur and nitrogen doped carbon materials Ni-MOF electrocatalysts for oxygen evolution reaction

Sulfur-nitrogen doped porous carbon (SNPC) material was first synthesized by the hydrothermal method and high-temperature carbonization. Then, the three-dimensional cube SNPC-Ni-metal organic frameworks (SNPC-Ni-MOF) composite was finally synthesized by hydrothermal method and applied in oxygen evolution reaction (OER). BET analysis proved the porosity and higher specific surface area of SNPC. FTIR analysis implied that the coordination of trimesic acid with metal ions was successful. SEM images showed that the as-synthesized carbon materials presented beautiful spherical. The overpotential of the as-synthesized composite was conducted by the LSV test, and it was found that the SNPC-Ni-MOF composite exhibited the lower overpotential (400 mV). Electrochemical impedance spectroscopy showed the SNPC-Ni-MOF had the smaller R-ct value (1.744 omega cm(-2)). Tafel plot indicated that the doping of sulfur and nitrogen improved the electrochemical properties of carbon materials to some extent. The cyclic voltammetry test illustrated that the electrochemical active surface area of SNPC-Ni-MOF was 48.75 cm(2). The turnover frequency for OER was 0.016 s(-1). In addition, the i-t curve test indicated that the SNPC-Ni-MOF composite possessed better stability, the retention rate reaches 96.7% after 20,000 cycles. All results illustrate that the OER performance of the as-prepared SNPC-Ni-MOF composite has been improved and can be used as electro-catalysts for water splitting.