Artificial Photosynthetic System with Spatial Dual Reduction Site Enabling Enhanced Solar Hydrogen Production.

Despite the potential of the S-scheme artificial photosynthetic system in driving photocatalytic hydrogen generation, conventional approaches tend to focus too heavily on a single reduction site. These systems still suffer poor redox ability and charge separation impairing the photocatalytic hydrogen evolution reaction. To overcome this limitation, we propose a novel strategy of designing a double S-scheme system that leverages dual reduction sites, thereby preserving energetic photo-electrons and holes to enhance apparent quantum efficiency. In this work, we put forth a double S-scheme junction consisting of CdS nanospheres decorated with anatase TiO 2 nanoparticles coupled with graphitic carbon nitride. The as-prepared catalyst exhibits a remarkable hydrogen evolution rate of 26.84 mmol g -1 h -1 and an apparent quantum efficiency as high as 40.2% at the wavelength of 365 nm. This enhancement of photocatalytic hydrogen evolution performance is ascribed to the efficient separation and transportation induced by the double S-scheme. Supporting this, both theoretical calculations and comprehensive spectroscopy tests (both in-situ and ex-situ) affirm the efficient charge transportation across the catalyst interface. Moreover, substituting the reduction-type catalyst CdS with other similar sulfides like ZnIn 2 S 4 , ZnS, MoS 2 and In 2 S 3 further confirms the feasibility of the proposed double S-scheme configuration. Our findings provide a pathway to designing more effective double S-scheme artificial photosynthetic systems, opening up fresh perspectives in enhancing photocatalytic hydrogen evolution performance. This article is protected by copyright. All rights reserved.