An Integrated Device for Converting Water, Carbon Dioxide and Light into Electricity and Organics

Abstract

© The Author(s) 2017. Published by ECS. All rights reserved. Global warming presents an ever-rising challenge to humans today, caused by an unprecedented rise in the carbon dioxide levels in the atmosphere over the past decade. This study proposes a way to fix this problem in a sustainable way using sunlight to convert CO 2 into useful fuels through a novel device. A Simulink model of photo-voltaic cell, CO 2 electrochemical reduction and photo-electrochemical reduction cell is developed and integrated together to model the device. The photo-voltaic cell model takes solar irradiation and temperature as inputs, giving electrical power as output. The CO 2 electrochemical reduction cell model consists of three blocks, anode, cathode and voltage. Mole balances on anode and cathode give the product flow-rates. Nernst and Butler-Volmer equations calculate the voltage required to operate the CO 2 reduction cell. The CO 2 photo-electrochemical reduction cell calculates product flow rates and voltage required to operate the cell using continuity, charge balance and Butler-Volmer equations. The model of the integrated device calculates i-V characteristics of the photovoltaic, electrochemical reduction and photo-electrochemical reduction cell under different environmental conditions, the product flow rates, contribution of various cell over-voltages. The model developed predicts photo-electrochemical route to be more energy and area efficient as compared to the electrochemical route.