Elemental red phosphorus (RP) has an ultra-low activity of splitting water for H 2 and O 2 evolution. In this study, RP was decorated by trace amount of WO 3 to greatly enhance the photocarriers separation and photocatalytic activity for overall water splitting under visible light. The 2.5% WO 3 /RP composite achieved the highest activity to produce H 2 and O 2 , and the activity was 7.0 times that of pure RP under visible light (λ ≥ 420 nm). The significantly increased photocarriers separation of WO 3 /RP was ensured by transient photocurrent, electrochemical impendence, photoluminescence, and time-resolved photoluminescence characterizations. More importantly, WO 3 /RP maintained high stability when it was persistently used for 20 cycles. Based on the reactive oxygen species ( O 2 − and OH) detected during the photocatalytic process, an S-scheme mechanism was proposed for WO 3 /RP composites to efficiently separate the photocarriers. This work provides a notion for improving the overall water splitting activity of RP via an S-scheme photocarriers separation mode.
Zhipeng Xie,Lu Wang,Yuhui Cheng,Qian Guo,Haibo Zhou,Congshu Huang,Jingjing Wang,Weifeng Bu
Improving the performance of antifouling coating under illumination-involved harsh environments is of prime scientific and engineering importance. However, it still remains a big challenge due to the strong photo-corrosion character of cuprous oxide (Cu 2 O) that works as the most widely-used primary antifoulant. To address this issue, a novel heterojunction of Cu 2 O@TiO 2 was constructed by in situ adsorption-hydrolysis approach. The as-designed heterojunction structure endows superior photo-stability with Cu 2 O@TiO 2 , which has been proven to proceed via S-scheme mechanism by a set of complementary characterizations including in situ XPS and EPR. As anticipated, the resulted Cu 2 O@TiO 2 coating manifests excellent stability and antifouling performance under illumination-involved mimetic service conditions such as dry-dock and waterline environments, as substantiated by the bioassays and marine field trials. A dual-target photo-synergized enhancing mechanism for the S-scheme Cu 2 O@TiO 2 could be deduced as to: (i) inhibit the accumulation of holes on Cu 2 O to exert a stabilization effect; (ii) boost the generation of reactive oxygen species (ROS, including HO /O 2 − ) to enhance the antifouling property. The methodology provides a proof-of-concept design to fabricate high photo-stable Cu 2 O-based antifoulant materials, with the gain in understanding the intrinsic failure principle of coatings and the biocidal mechanism of cuprous oxide toward marine application.
Yi Yang,Jingjing Liu,Miaoli Gu,Bei Cheng,Linxi Wang,Jiaguo Yu
Coupling photocatalytic H 2 O 2 evolution with simultaneous furfuryl alcohol oxidation can avoid the slow water oxidation reaction and fully utilize photogenerated carriers to produce valuable chemicals. Herein, a COF (denoted as BTTA) was synthesized by the Schiff-base condensation and in-situ grown on the surface of TiO 2 nanofibers. The resultant TiO 2 /BTTA composite has a large interface and a short carrier migration distance. Furthermore, the porous and ultrathin BTTA layers endow the composites abundant active sites and excellent light absorption ability. Remarkably, a H 2 O 2 -evolution rate of 740 μmol L −1 h −1 and a furoic alcohol conversion of 96 % are achieved. In-situ irradiated X-ray photoelectron spectroscopy and electron spin resonance confirm the S-scheme carrier transfer mechanism, which spatially separates photogenerated carriers with strong redox power. This work opens a new door to the rational design of S-scheme photocatalysts for economic and green photosynthesis of H 2 O 2 and organic compounds.
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