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Oxygen-defective Bi 2 MoO 6 /g-C 3 N 4 hollow tubulars S-scheme heterojunctions are fabricated by hydrothermal and calcination methods and show excellent photocatalytic performance. The S-Scheme heterojunction accelerates the effective charge separation and transfer by internal electric field (IEF) and energy band bending at the interface, thus improving the photocatalytic performance. [Display omitted] Novel S-scheme heterojunction photocatalysts of bismuth molybdate/hollow tube graphite carbon nitride (Bi 2 MoO 6 SOVs/g-C 3 N 4) containing surface defects (SOVs) were prepared by calcination and hydrothermal methods. The hollow tubular structure of g-C 3 N 4 facilitates the enhancement of multiple reflection and scattering of light, and also have a larger range of specific surface areas and more reactive sites, which promotes carrier separation and thus improves photocatalytic performance. The introduction of SOVs to bismuth molybdate not only reduces the band gap of bismuth molybdate, but also promotes the separation of charges. The optimized Bi 2 MoO 6 SOVs/TCN photocatalyst has a hydrogen production efficiency of 2.29 mmol h−1 g−1. It also shows high photocatalytic degradation property of tetracycline and bisphenol A in water, up to 97.3 % and 98.9 %, respectively. Meanwhile, the transfer mechanism of photogenerated charges in S-scheme heterojunctions can be verified by electron paramagnetic resonance and in situ irradiated x-ray photoelectron spectroscopy electron paramagnetic resonance, which accelerated the separation and transfer of photogenerated charge by energy band bending at the interface and internal electric field. This rational structural design strategy provides a new development idea for building high-performance S-scheme heterojunction photocatalysts. [ABSTRACT FROM AUTHOR]

Polydopamine/defective ultrathin mesoporous graphitic carbon nitride Z-scheme organic assembly is fabricated via N -vacancy defects and π-π interactions, which exhibits robust photocatalytic H 2 production and contaminant degradation, due to the direct Z-scheme charge transfer mechanism to realize efficient spatial charge separation, and the enhanced photothermal effect to promote the photocatalytic reaction. [Display omitted] • Polydopamine/defective ultrathin mesoporous graphitic carbon nitride organic assemblies are fabricated. • N -vacancy and π-π interactions provide strong connection and fast charge transfer. • Z-scheme structure enables efficient of photogenerated charges separation. • Polydopamine extends photoabsorption and produces photothermal effect to improve catalyze activity. Polydopamine/defective ultrathin mesoporous graphitic carbon nitride (PDA/DCN) Z-scheme organic assembly is fabricated through high-temperature surface hydrogenation and ultrasonic freeze-dried strategies. PDA could be anchored on the surface of DCN with adequate N -vacancy defects firmly via π-π interactions, forming Z-scheme heterogenous structure for promoting charge separation. The visible and near-infrared light driven photocatalytic hydrogen evolution rate is up to 3420 μmol h−1 g−1, and the removal ratio of organic contaminant methylene blue is up to 98% within 70 min, which is several times higher than that of pristine graphitic carbon nitride and DCN. The important reason is the defects of DCN not only enhance the interaction with PDA, but also make the obvious polarized inbuilt electric field, and lead to Z-scheme structure for effective charge separation and rapid transfer, which is also confirmed by density functional theory (DFT) calculations. In addition, PDA extends the photoresponse to the near-infrared region and induces obvious photothermal effect to increase the reaction rate of the photocatalytic system. The efficient photothermal conversion of PDA/DCN should be another reason for the enhanced photocatalytic performance. [ABSTRACT FROM AUTHOR]