Artificial photosynthesis of ethanol using type-II g-C3N4/ZnTe heterojunction in photoelectrochemical CO2 reduction system

By Qinglong Wang, Xikui Wang, Zehui Yu, Xingxing Jiang, Jinjin Chen, Leiming Tao, Mingkui Wang, Yan Shen. Nano Energy, 2019

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Abstract Constructing heterojunctions and designing advanced structures to mimic natural photosynthesis is an effective route to convert CO2 into high-energy chemicals with high efficiency and selectivity. Compared to a single-component catalyst, those of two components with different function can corporately facilitate the formation of C2 products. Herein, a type-II heterojunction based on graphitic carbon nitride (g-C3N4)/ZnTe was constructed for the first time for photoelectrochemical CO2 reduction, yielding an impressive ethanol generation rate of 17.1 μmol cm−2 h−1 at -1.1 V (vs. Ag/AgCl). The heterojunction accelerates separation of photo-generated electron-hole pairs and transfer of electrons from ZnTe to g-C3N4 driving by an interfacial internal electric field (IEF) formed between the two semiconductors. Moreover, the combination of ZnTe of high CO2 adsorption capacity serves as CO-producing site with g-C3N4 featuring of abundant pyridinic N subsequently accomplishes the C-C coupling process via adsorbing CO and proton-coupled electron transfer. A pipelined mechanism to rationalize the selective reduction of CO2 to ethanol is proposed and discussed.

Subfields: Materials Chemistry, Renewable Energy, Sustainability and the Environment

View Paper: https://www.semanticscholar.org/paper/42f2b361f7463e84697f41b25c61df7d9ee8c75b