We studied CO2 reduction using a solar cell driven photoelectrochemical (PEC) reactor in dilute aqueous KHCO3 (0.1 M) solution. Results show that CO2 was reduced to four major hydrocarbon species, namely, formic acid (HOOH), formaldehyde (HCOH), methanol (CH3OH), and methane (CH4). Over a reaction time of 5 h, the product yield was 1.55, 0.62, 2.02, and 2.16 mu M with a current efficiency of 0.22%, 0.17%, 0.84% and 1.2%, for HCOOH, HCOH, CH3OH, and CH4, respectively, whereas hydrogen, produced from water electrolysis, exhibited the highest current efficiency of 54.23%. It is also noted that the production of organic carbons was enhanced by increasing the CO2 concentration due to the presence of methanol. Results showed that methanol hindered hydrogen formation and increased the yield of organic carbons. Furthermore, the degradation of an azo dye, namely, methyl orange (MO) was observed using PEC process under different applied currents. The degradation rate was increased by two orders of magnitude when a bias potential was applied to the solar cell system. Our results demonstrated the potential of solar energy for CO2 conversion to energy-rich organic carbons and the remediation/purification of impaired water. (c) 2013 Elsevier B.V. All rights reserved.