© 2021An eco-friendly hybrid nanomaterial, the cobalt supported on nano-hydroxyapatite (Co3O4@nHAP), which the nano-hydroxyapatite (nHAP) is a promising material for catalytic systems because of immobilization stability with metals or complexes, was fabricated by ultraviolet irradiation and calcination. The prepared hybrid nanomaterial (Co3O4@nHAP) was characterized by FT-IR, XRD, FESEM, EDX, and mapping, and the cobalt ions were founded to be incorporated into the hydroxyapatite surface. The Co3O4@nHAP nanomaterial was used as a catalyst in the reduction of 2-nitrophenol (2-NP) and Rhodamine B (Rh B) and for the first time, the Co3O4@nHAP type nanomaterial was tested as a counter electrode in the dye-sensitized solar cells (DSSC). The catalytic conversions of Co3O4@nHAP nanomaterial were founded as 97.8% at 12 min. for 2-NP and 86.7% at 15 min. for Rh B and the reusability work for the 2-NP was performed as I - V cycles between 97.8%, to 85.8%, respectively. Also, the power conversion efficiencies (PCEs) of Co3O4@nHAP and Co3O4@nHAP/CNT in the DSSC devices as a counter electrode (reduction layer) were recorded as 0.05% and 0.36%, respectively. These model tests for the development of low cost and effective catalysts show promise.