Rational three-dimensional nitrogen doped mesoporous carbon nanostructured surfaced Nickel metal (Ni) nanoparticles (nps), NCNP composites have been developed using nickel organic complex and utilized as an electrocatalyst for oxygen evolution reaction. The NCNP composites of tunable physio-chemical characteristics, such as Ni nps size (similar to 18-similar to 42 nm), surface area (similar to 18-similar to 43m2 g(-1)), pore size (3.23-3.84 nm) and nitrogen doping amount (1.20-3.87 wt%) have been achieved via controlled carbonization temperature. An optimized NCNP composite of favorable physio-chemical properties has delivered good oxygen evolution kinetics such as a lower overpotential value (370 mV) at 10mA cm(-2), a minimum Tafel slope value (55 mV dec(-1)), and relatively a higher electrochemical surface area (0.6325 cm(-2)) than the other NCNP composites. Moreover, the best NCNP electrocatalyst has shown a comparable overpotential value with the benchmarking catalyst at 10mA cm(-2), equivalent to similar to 0% solar photoelectrical conversion efficiency. In addition, the best NCNP electrocatalyst has exhibited excellent accelerated degradation test for 24 h at a constant current density of 10 mAcm(-2) with an increase overpotential value of 0.029 V. (c) 2019 Published by Elsevier Ltd.