Catalytic photo-reduction of CO2 is a sustainable process that allows to control emissions and to remove the excess CO2 in the atmosphere, in addition, photo catalysts convert carbon dioxide and water into solid chemical compounds such as coal, into liquids such as methanol (CH3OH), ethanol (C2H5OH) and formic acid (HCOOH) and into gaseous such as methane (CH4), carbon monoxide (CO) and formaldehyde (HCHO). We produced Cu2O nanoparticles to develop an artificial photosynthesis process to convert CO2 and water into methanol. Our artificial leaf uses the same portion of green light as the visible spectrum used by plants during natural photosynthesis.