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Abstract As a promising way to control greenhouse gas emission and alleviate global energy shortage, photocatalytic reduction of carbon dioxide attracts more attentions in recent years since it can produce fuels efficiently with the combination of H 2 through water splitting. In this work, a computational model which characterizes the photocatalytic reduction of carbon dioxide by CO co-feed in a novel twin reactor is developed with three subsidiaries of chemical reaction kinetics, gas–liquid mass transfer, and transient sun light intensity distribution. Thanks to previous experimental work as the reliable verification for the numerical simulation, the variations of the CH 3 OH concentration with the CO/CO 2 ratio of gas mixture, pressure and temperature are obtained and analyzed. The results show that the carbon in CO can form CH 3 OH directly, however the excessive CO will react with HCOOCH 3 to form CH 3 CHO, which results in a reduced CH 3 OH concentration. Besides, the CH 3 OH concentration subsequently increases as the temperature and pressure increase, and the CH 3 OH product and reaction rate vary widely with time due to the changing sun light intensity during the day.

Abstract The production of valued added fuels and chemicals via photocatalytic carbon dioxide reduction has attracted increasing attentions in recent years. Based on the traditional twin reactor configuration, a novel bubbling twin reactor is proposed to improve the conversion of carbon dioxide to methanol in this work. The multiphysical model for the bubbling twin reactor is developed and numerically simulated. The variations of the methanol production with the gas inlet flow velocity and gas inlet number are obtained. The results show that the bubbling twin reactor has a higher carbon dioxide conversion efficiency than the traditional one. Moreover, the methanol production subsequently increases as the gas inlet velocity increases. With the constant inlet gas volumetric flow rate, the production of methanol can be improved by increasing the gas inlet number.