Tandem ohmic junction-enhanced electron coupling effect in FeCoP@NC/ ZnCdS for boosting photocatalytic hydrogen production

Rationally engineered heterojunction photocatalysts are an effective strategy to enhance the efficiency of photogenerated charge separation. In this work, a fascinating tandem FeCoP@NC/ZnCdS heterojunction is aimfully designed for effectively enhancing the charge separation kinetics of the ZnCdS via the synergistic strategy of double ohmic junction and strong electron coupling effect between FeCoP@NC and ZnCdS. The N-doped carbon coated FeCoP (FeCoP@NC) hererostructure is derived from in-situ phosphating Fe-Co-Co Prussian blue analog (Fe-Co-Co PBA). The N-doped carbon layer provides a fast charge transfer channel, which extracts the photo- generated electrons from the ZnCdS leads to effective charge separation due to the FeCoP@NC/ZnCdS ohmic junction. Besides, the strong electron coupling effect, achieved through gradient charge transfer within the FeCoP@NC/ZnCdS ohmic junction, significantly boosts photocatalytic activity. Consequently, the optimized 20%FeCoP@NC/ZnCdS manifests notably enhanced photocatalytic H2 production activity (32.36 mmol g-1h- 1) with an exceptional apparent quantum efficiency of 17.89 % at 420 nm, which is 14.6 and 179.8 folds greater than ZnCdS and FeCoP@NC, respectively. This work provides an innovative strategy for constructing tandem heterojunctions to improve charge separation kinetics of the ZnCdS with outsatanding photocatalytic performance.