Artificial photosynthesis of value-added chemicals from CO₂ and water has received renewed attention and diverse technical solutions for high efficiency and durability systems have been explored. The photoelectrochemical (PEC) systems have been demonstrated to be technically viable with a number of semiconductor photoanodes (e.g., WO₃, BiVO₄, etc.) coupled to metal (Cu, Au, Ag, etc.) or metal oxide electrodes (CuO and Cu₂O), as well as photocathodes (Si, Cu₂O, CuO₂, CuFeO₂, etc.) coupled to metal/metal oxide anodes for CO₂ photoconversion. A photoelectrochemical cell, composed of WO₃/dye-sensitized solar cell and copper oxide wire arrays, is demonstrated as an unassisted, durable device for CO₂ photoconversion. The high surface-to-volume copper oxide wire exhibits a promising electrocatalytic activity of CO₂ reduction reaction at faradaic efficiencies of ~80% and ~60% at E = -0.2 and -0.4 V vs. RHE, respectively. The single-absorber cell of a WO₃ photoanode and copper oxide wire cathode couple requires the minimum overpotential (h) of 0.7 V to drive CO₂ conversion. In the unassisted cell, the long-wave band (l > ~450 nm) passes through the semi-transparent WO₃ film is absorbed by dye. The unassisted cell shows a potential gain of ~0.7 V, successfully driving the CO₂ conversion without any external power supply.