Improved photocatalytic activity and stability of InGaN quantum dots/C 3 N 4 heterojunction photoelectrode for CO 2 reduction and hydrogen production

Abstract Photocatalytic conversion of CO 2 to produce fuel is considered a promising approach to reduce CO 2 emissions and tackle energy crisis. GaN-based materials have been studied for CO 2 reduction because of their excellent optical properties and band structure. However, low photocatalytic activity and severe photocorrosion of GaN-based photoelectrode greatly limit their applications. In this work, photocatalytic activity was improved by adopting InGaN quantum dots (QDs) combined with C 3 N 4 nano-sheets as photoanode, and thus the efficiency of CO 2 reduction and the selectivity of hydrogen production were increased significantly. In addition, the photoelectron-chemical corrosion of photoelectrodes has been apparently controlled. InGaN QDs/C 3 N 4 has the highest CO and H 2 productions rates of 14.69 μ mol mol −1 h −1 and 140 μ mol mol −1 h −1 which were 2.2 times and 14.5 times than that of InGaN film photoelectrode, respectively. The enhancement of photocatalytic activity is attributed to C 3 N 4 modification and a large electric dipole forming on the surface of InGaN QDs, which facilitate the separation and transfer of photo-generated carriers and thus promote CO 2 reduction reaction. This work provides a promising strategy for the development of GaN-based photoanodes with superior stability and efficiency.