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Ag-polydopamine nanoparticles co-decorated defective mesoporous carbon nitride assembly with wide spectrum response is fabricated, which exhibits robust photothermal-photocatalytic H 2 production, due to Ag-PDA not only extends the light absorption of DCN, but also forms an efficient Z-scheme charge transfer path with DCN, enabling fast electron transfer. [Display omitted] • Ag-polydopamine nanoparticles co-decorated defective mesoporous carbon nitride assemblies are fabricated. • Ag-polydopamine nanoparticles co-decorated promote efficient charge transfer. • Small-sized Ag nanoparticles as efficient cocatalysts enables efficient charge separation. • Ag-polydopamine extends photoabsorption and produces obvious photothermal effect to improve catalyze activity. • The formation of Z-scheme charge transfer mechanism favors spatial charge separation. Ag-polydopamine nanoparticles co-decorated defective mesoporous carbon nitride nanosheets assemblies (Ag-PDA/DCN) with wide spectrum responseare fabricated. The Ag-PDA/DCN assemblies exhibit excellent photocatalytic hydrogen production performance. The visible light and near-infrared light driven photocatalytic hydrogen evolution rate is up to 3840 μmol h−1 g−1, which is 20 and 7 times higher than those of DCN and PDA/DCN, respectively. This is mainly because the Ag-polydopamine nanoparticles not only form an efficient carrier transport path and realize fast electron transport, but also further extend the photoresponse of DCN, resulting in an obvious photothermal effect to further improve the photocatalytic activity. More importantly, the formed Ag nanoparticles by the low-temperature photodeposition method is smaller in size and better in dispersibility. Ag nanoparticles act as a co-catalyst in Ag-PDA/DCN, which can effectively separate the spatially photogenerated charge carriers. Compared to three systems with different Ag decoration positions, Ag-PDA/DCN with Z-scheme charge transfer mechanism is more favorable for promoting photocatalytic performance. This co-decorated strategy provides a new idea for developing low-cost Pt-free photocatalysts for solar energy conversion. [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]