Au nanoparticle-controlled formation of metallic and oxidized Pt nanoparticles on graphitic carbon nitride nanosheets
Xin Guo1, Lina Kong1, Jianping Xu1
1School of Materials Science and Engineering, Institute of Material Physics, Key Laboratory of Display Materials and Photoelectric Devices, Ministry of Education, and Tianjin Key Laboratory for Photoelectric Materials and Devices, and National Demonstration Center for Experimental Function Materials Education, Tianjin University of Technology, Tianjin 300384, China. kongln@email.tjut.edu.cn lilan@tjut.edu.cn.
Abstract:
Surface decoration of noble-metal cocatalysts on graphitic phase carbon nitride (g-C3N4) with high efficiency and trace content for water splitting is exciting but difficult to achieve. Herein, we report the anchoring of Au and metallic/oxidized Pt nanoparticles (NPs) on g-C3N4 as cocatalysts via a photoreduction process for enhancing photocatalytic H2 production. Au NPs are preferentially decorated on g-C3N4, which can control the formation of metallic/oxidized Pt complex species. The well dispersed Au and metallic/oxidized Pt NPs improved the light-harvesting and the photo-generated carrier separation of g-C3N4. G-C3N4 sequentially decorated with Au (0.3 wt%) and metallic/oxidized Pt (0.3 wt%) cocatalysts, exhibited the highest and stable H2 evolution rates of 2560 and 139 μmol h-1 g-1 under simulated sunlight and visible light (λ ≥ 420 nm) irradiation, respectively, compared to the samples that are simultaneously and sequentially decorated with the same content of Pt and Au on g-C3N4. The enhanced photocatalytic activity is attributed to the synergistic effect of Au and metallic/oxidized Pt cocatalysts, i.e., the effective localized surface plasma resonance coupling between Pt and Au NPs, as well as electron-sink function of metallic Pt, which promote the generation and transfer of more carriers from g-C3N4 to the Pt species, in addition to the superior hydrogen evolution capacity of metallic and oxidized Pt. This work maximizes the performance of noble-metal cocatalysts with minimized content and provides the possibility of realizing efficient solar-to-fuel conversion.
