Built-in electric field intensified by photothermoelectric effect drives charge separation over Z-scheme 3D/2D In 2 Se 3 /PCN heterojunction for high-efficiency photocatalytic CO 2 reduction

It is a challenging issue to further drive charge separation through the oriented design of Z-scheme heterojunction in the exploitation of cost-effective photocatalytic materials. In this contribution, the unique Z-scheme 3D/2D In 2 Se 3 /PCN heterojunction is developed through implanting In 2 Se 3 microspheres on PCN nanosheets using an in situ growth technique, which acquires the effective CO generation activity from photocatalytic CO 2 reduction (CO 2 R). The CO yield of 4 h in the CO 2 R reaction over the optimal In 2 Se 3 /PCN-15 sample reaches up to 11.40 and 2.41 times higher than that of individual PCN and In 2 Se 3 , respectively. Such greatly enhanced photocatalytic performance is primarily the improvement of photogenerated carrier separation efficiency. To be more specific, the formed built-in electric field is significantly intensified by producing the temperature difference potential between In 2 Se 3 and PCN owing to the photothermoelectric effect of In 2 Se 3 , which actuates the high-efficiency separation of photogenerated charge carriers along the Z-scheme transfer path in the In 2 Se 3 /PCN heterojunction. The effective strategy of enhancing the built-in electric field to drive photogenerated charge separation proposed in this work opens up an innovative avenue to design Z-scheme heterojunction applied to high-efficiency photocatalytic reactions, such as hydrogen generation from water splitting, CO 2 R, and degradation of organic pollutants.(c) 2023 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.