A challenge in photocatalysis consists in improving the efficiency by harnessing a large portion of the solar spectrum. We report the design and realization of a robust molecular-semiconductor photocatalytic system (MSPS) consisting of an earth-abundant phytic acid nickel (PA-Ni) biomimetic complex and polymeric carbon nitride (PCN). The MSPS exhibits an outstanding activity at l = 940 nm with high apparent quantum efficiency (AQE) of 2.8 %, particularly l > 900 nm, as it outperforms all reported state-of-the-art nearinfrared (NIR) hybrid photocatalysts without adding any noble metals. The optimum hydrogen (H 2) production activity was about 52 and 64 times higher with respect to its pristine counterpart under the AM 1.5 G and visible irradiation, respectively, being equivalent to the platinum-assisted PCN. This work sheds light on feasible avenues to prepare highly active, stable, cheap NIR-harvesting photosystems toward sustainable and scalable solar-to-H 2 production.

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Semiconductor quantum dots (QDs) have shown excellent advantages in photocatalysis owing to the unique optical properties, adjustable bandgap, and high specific surface area. However, the small size of QDs also brought severe charge recombination and particle agglomeration issues. Here, a simple QD-mediated precipitation method was used to create 0D/2D nanocomposites of Zn-AgIn 5 S 8 QDs anchored onto NiS nanosheets. The ultrathin Zn-AgIn 5 S 8 /NiS nanocomposites show obvious photocatalytic hydrogen production capacity due to the abundant active sites and efficient charge transportation in NiS nanosheets. With 7% of NiS, the maximized H 2 evolution rate reached 5.2 mmol g −1 h −1 , 11 times that of pure QDs. The apparent quantum efficiency of H 2 production achieves 14.9% at 420 nm at 5 °C. Interestingly, the maximum activity was achieved with 7% of NiS, higher than the normally used cocatalysts of 1−3%, which may be attributed to the ultrathin nature of the NiS nanosheets that simultaneously promoted the charge separation and catalytic activity but with minimized light-shielding effect. A reasonable mechanism of 0D/2D nanocomposite photocatalyst was proposed. This study supplies a simple QD-mediated precipitation method for the construction of ultrathin 0D/2D nanocomposites and also a novel strategy to improve the efficiency of sulfide photocatalysts.

Photoassisted electrocatalysis (P-EC) emerges as a rising star for hydrogen production by embedding photoactive species in electrocatalysts, for which the interfacial structure design and charge transfer kinetics of the multifunctional catalysts remain a great challenge. Herein, Zn-AgIn 5 S 8 quantum dots (ZAIS QDs) were embedded into 2D NiFe layered double hydroxide nanosheets through a simple hydrothermal treatment to form 0D/2D composite catalysts for P-EC. With evidence from transient photovoltage spectroscopy, we acquired a clear and fundamental understanding on the kinetics of charge extraction time and extraction amount in the 0D/2D heterojunctions that was proved to play a key role in P-EC. Upon light illumination, for HER, the optimized NiFe-ZAIS exhibits obviously reduced overpotentials of 129 and 242 mV at current densities of 10 and 50 mA cm −2 , which are 22 and 33 mV lower than those of dark electrocatalysis, respectively. For OER, the NiFe-ZAIS electrode also shows low overpotentials of 220 and 268 mV at current densities of 10 and 50 mA cm −2 , respectively, under light illumination, which were able to almost double the intrinsic activity. Finally, with NF@NiFe-ZAIS as both the cathode and the anode, the assembled electrolyzer only requires 1.62 V to reach the overall water splitting current density of 10 mA cm −2 under P-EC. This work provides a useful example for the profound understanding of the design and the kinetics study of multifunctional P-EC catalysts.