Herein, we elucidate the pulsed laser irradiation (PLI)–driven conversion of NiO, Co 3O 4, and NiCo 2O 4 into their respective Ni, Co, and NiCo alloys in ethanol without adding reducing agents. Multiple characterization analyses reveal that continuous PLI melts and fuses aggregated oxides into single alloy particles. Ethanol decomposition products act as in situ reductants, enabling efficient oxide-to-metal transformation. Furthermore, the electrocatalytic oxygen evolution reaction (OER) activity of the Ni, Co, and NiCo alloys was examined in an alkaline electrolyte. Notably, the bimetallic NiCo alloy exhibited superior OER activity, delivering a lower overpotential of 399 mV at 10 mA⋅cm −2 than single Ni (461 mV) and Co (437 mV). A water electrolyzer constructed with NiCo alloy (+)∥Pt/C (−) couple required a low cell voltage of 1.67 V at 10 mA⋅cm −2 . In situ Raman spectroscopy, complemented by density functional theory (DFT) calculations, reveals that the enhanced OER activity of the NiCo alloy originates from optimized adsorption energies of key reaction intermediates, attributed to synergistic electronic contacts between Ni and Co atoms. This work not only clarifies the mechanism of PLI-induced reduction of metal oxides to alloy nanoparticles but also demonstrates their promise as efficient electrocatalysts for water oxidation and green hydrogen generation.