Pyrene-benzothiadiazole-based Polymer/CdS 2D/2D Organic/Inorganic Hybrid S-scheme Heterojunction for Efficient Photocatalytic H_(2) Evolution

Nowadays,conjugated polymers have garnered numerous attention as a new class of organic photocatalysts due to their tunable electronic properties,low cost,excellent stability and sufficient light-absorption performance.In particular,pyrene-benzothiadiazole-based conjugated polymer(PBBP)has been considered to be a new type of conjugated polymers for photocatalytic H_(2)evolution.However,the poor charge separation seriously limits its practical application in H_(2)evolution.In this work,a PBBP-based polymer/CdS 2D/2D organic/inorganic S-scheme heterojunction photocatalyst with a strong internal electric field is,for the first time,prepared for efficient photo-catalytic hydrogen evolution.The pyrene-benzothiadiazole-based conjugated polymers(PBBP)are synthesized by the Suzuki-Miyaura reactions.Then,the hybrid heterojunction photocatalysts are fabricated by coupling CdS with it through the ultrasonic mixing method.As a result,the highest H_(2)-production rate of 15.83 mmolh^(-1)g^(-1)is achieved on 20%PBBP/CdS composite under visible-light irradiation,nearly 2.7 times higher than that of pure CdS.The apparent quantum efficiency(AQE)of 20%PBBP/CdS composite could reach 8.66%atλ=420 nm.The enhanced activity could be attributed to the construction of S-scheme heterojunction,which accelerates the recombination of carriers with weaker redox ability and maintains the strong reducibility of electrons in CdS.This work provides a protocol for pyrene-benzothiadiazole-based conjugated polymers to prepare S-scheme heterojunction photocatalysts based on organic/inorganic coupling.