Hybrid Cu(x)O–TiO(2) Heterostructured Composites for Photocatalytic CO(2) Reduction into Methane Using Solar Irradiation: Sunlight into Fuel

[Image: see text] Photocatalytic CO(2) conversion to fuel offers an exciting prospect for solar energy storage and transportation thereof. Several photocatalysts have been employed for CO(2) photoreduction; the challenge of realizing a low-cost, readily synthesized photocorrosion-stable photocatalytic material that absorbs and successfully utilizes a broad portion of the solar spectrum energy is as yet unmet. Herein, a mesoporous p-type/n-type heterojunction material, Cu(x)O–TiO(2) (x = 1, 2), is synthesized via annealing of Cu/Cu(2)O nanocomposites mixed with a TiO(2) precursor (TiCl(4)). Such an experimental approach in which two materials of diverse bandgaps are coupled provides a simultaneous opportunity for greater light absorption and rapid charge separation because of the intrinsic p–n heterojunction nature of the material. As detailed herein, this heterostructured photocatalyst demonstrates an improved photocatalytic activity. With the CO(2) reduction of our optimal sample (augmented light absorption, efficacious charge separation, and mesoporosity) that utilizes no metal cocatalysts, a remarkable methane yield of 221.63 ppm·g(−1)·h(−1) is achieved.