Enhanced photoresponse and fast charge transfer: three-dimensional macroporous g-C 3 N 4 /GO-TiO 2 nanostructure for hydrogen evolution

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2020-09, Vol.8 (37), p.19533-19543
• Main Authors: Li, Wei, Ma, Qiong, Wang, Xiao, Chu, Xiao-shan, Wang, Fei, Wang, Xue-chuan, Wang, Chuan-yi
• Format: Article
• Language: English
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/D0TA07178A

Utilizing solar light to produce hydrogen is an advanced strategy to alleviate the energy crisis. Graphitic carbon nitride (g-C 3 N 4 ) and graphene oxide (GO) have demonstrated significant potential in synthesizing highly efficient photocatalysts due to their favorable charge separation and transfer. However, the simple 2D structure generally leads to a weak adhesion to the surface cocatalyst, which negatively affects the photoresponse, interfacial charge transfer and durability of the resultant photocatalyst. Herein, we designed a 3D macroporous g-C 3 N 4 /GO (p-CNG) skeleton to enhance the adhesion stability of the cocatalyst (anatase TiO 2 NPs). The typical macroporous structure remarkably increased the BET surface area (65.81 m 2 g −1 ) of the 3D p-CNG skeleton, which was 2.5-fold greater than that of the nonporous 3D CNG composite. The enhanced adhesion of the anatase TiO 2 NPs on the 3D p-CNG skeleton promoted the formation of a heterointerface, leading to the fast interfacial charge transfer and improved photoresponse. Hence, the optimal 3D p-CNG/TiO 2 (p-CNGT) catalyst represented excellent HER activity (33.1 μmol g −1 h −1 ) under the simulated solar light, which was 8.9-fold greater than that of the pristine anatase TiO 2 NPs and 4.7-fold greater than that of the 3D p-CNG skeleton. Therefore, the high apparent quantum yield (12.4%) was achieved under illumination of λ = 400 nm. Due to the stable interfacial adhesion, the resultant catalyst represented excellent regenerability and durability during five cycles and 20 h of illumination. This work proposed an effective strategy for improving the HER activity and enhancing the durability of the existing catalyst.