Co-optimization of g-C3N4 with prolonging exciton lifetime strategy and co-catalyst strategy for enhanced photocatalytic H2 evolution activity
Nan Zhuang, Beihao Bai, Jin Liu, Yuwen Jiang
Abstract
In this work, the photocatalytic activity of g-C 3 N 4 is co-optimized for the first time using a strategy of prolonging exciton lifetime and a co-catalyst strategy. Amorphous CoB nanoparticles are loaded on OCN-K-CN, which is an O, K doped g-C 3 N 4 material with van der Waals heterojunctions inside. The optimized OCN-K-CN-CoB sample, containing 12 wt% CoB and 1.25% K 2 SO 4 in precursors, show photocatalytic H 2 evolution rate approximately 27 times higher than that of GCN. The mechanism of co-optimization is detailedly investigated through comparative experiments on light absorption , charge separation performance, and HER activity, with optimization strategy and CoB loading ratio as controlled variables. New roles of the two strategies have been revealed: "flux-limited reduction activity sites" for CoB and ''buffer-enhancer'' for OCN-K-CN. These new roles illustrate a hidden relationship between the optimizing effects of the two strategies and can explain a surprising advantage of this co-optimization: achieving near-optimal hydrogen evolution activity with significantly reduced co-catalyst loading ratio.