Incorporating cocatalysts to form Schottky junctions offers a promising strategy for enhancing photocatalytic performance, particularly in reducing environmental pollutants. This study introduces a novel method utilizing a two-dimensional nickel-based metal-organic framework (Ni-MOF), synthesized via a solvothermal process and partially derived for the decoration of nickel boride (NiB), establishing a Schottky junction photocatalyst. The hierarchically structured Ni-MOF/NiB was synthesized under ambient air conditions with varying molar ratios of NaBH4 (0.8, 1, and 1.2) and employed for Cr(VI) photocatalytic reduction. Among these ratios, the optimal Ni-MOF/NiB-1 exhibited a remarkable photocatalytic efficiency of 96% at pH = 2 under visible light within 75 min. This enhanced performance is attributed to the formation of the Schottky junction between NiB and Ni-MOF, facilitating effective charge carrier migration and separation, as well as the high surface area, numerous active sites, improved visible light absorption, and reduced recombination rate. This effective approach of anchoring a noble metal-free cocatalyst on a porous metal−organic framework creates an economical and sustainable photocatalyst to reduce Cr(VI).