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Photoenzymatic catalysis is an efficient strategy for selectively converting CO 2 into valuable chemicals. However, the sluggish reaction kinetics, resulting from low visible light utilization and rapid recombination of photogenerated carriers, severely inhibit the yields of target products. Herein, we present a novel artificial photosynthesis platform of 2D/2D MXene/crystalline COF-367 heterostructure for efficient conversion of CO 2 into HCOOH. This platform is extremely sensitive to solar light (λ ≤ 750 nm), with rapid charge separation and transfer due to the well-designed abundant ultrathin 2D/2D hetero-interfaces. Remarkably, Ti 3 C 2 /COF-367 achieves an impressive yield of 83.38% for coenzyme NADH regeneration with absence of electron mediator. Furthermore, it demonstrates a cascade ultra-high production rate of HCOOH at 1.88 mmol g−1 h−1 with almost 100 % selectivity. This work represents the first example of MXene to promote charge transfer in COFs-based photoenzymatic synergistic catalytic system, and provides insights into the development of organic/inorganic hybrids for CO 2 photoreduction. [Display omitted] • First example of MXene to promote charge transfer in COFs-based photoenzymatic catalytic system. • Ultrathin highly crystalline imine-linked COF-367 nanosheets were synthesized. • Abundant ultrathin 2D/2D hetero-interfaces for rapid charge separation/transfer. • Impressive NADH regeneration yield of 83.38% without electron mediator. • Ultra-high HCOOH production rate of 1.88 mmol g−1 h−1 with high selectivity. [ABSTRACT FROM AUTHOR]

Although hybrid solar cells take advantages of both inorganic and organic semiconductors for high performance, there have not been comparably photoelectric conversion efficiencies as expected from this kind of solar cells till now. The photoelectric response behavior of inorganic/organic hybrid solar cells has been explained on the theory of inorganic solar cells, but the distinctive wavelength dependent photoelectric character of organic semiconductors has not been well considered. In this work, Ag 2 S/organic bulk heterojunction solar cell devices were designed and fabricated in-situ on indium tin oxide (ITO) based on the direct metal surface elemental reaction (DMSER) method, to understand the corresponding photoinduced charge carrier dynamics under different wavelength light. The commonly used small molecule Spiro-OMeTAD and polymeric PTB7-Th were selected as the organic components of the fabricated solar cells. In Ag 2 S/Spiro-OMeTAD, Ag 2 S donated the charge carriers and controlled the photoinduced charge carrier dynamics of the devices at both 355 nm and 532 nm lights. Under 532 nm light, the PTB7-Th acted as hole transport materials (HTM) rather than charge carrier donor. These results indicated that hybrid thin films without wavelength dependent charge carrier dynamics is preferred for high performance solar cells. [ABSTRACT FROM AUTHOR]

An ultrathin layered 2D/2D van der Waals heterojunction of ReS 2 /high-crystalline g-C 3 N 4 is reported to significantly improve photocatalytic H 2 production attribute to its efficient charge transport, strong visible light harvesting, and suppressed recombination of photogenerated carriers. [Display omitted] • Ultrathin layered 2D/2D van der Waals heterojunction of ReS 2 /high-crystalline g-C 3 N 4. • Efficient charge transport of highly crystalline g-C 3 N 4 by eliminating deep defects. • Strong visible light harvesting, and excellent conductivity of ReS 2 nanoflakes. • Synergistic effect of rapid charge separation and transfer in 2D/2D heterojunction. • Superior photocatalytic H 2 -evolution efficiency of 3.46 mmol g−1h−1. Fabricating efficient nanocatalysts with excellent visible light response, coupled with rapid charge separation and transfer efficiency is still the most challenge for solar-driven hydrogen (H 2) evolution. Herein, an ultrathin layered 2D/2D van der Waals heterojunction of ReS 2 /high-crystalline g-C 3 N 4 (CCN) is constructed for the first time to significantly boost photocatalytic H 2 production. The as-prepared optimized 15% ReS 2 /CCN exhibits the highest H 2 -evolution rate of 3.46 mmol g−1h−1 under visible light irradiation, a 2.7 fold enhancements over that of pristine CCN and is also much higher than ReS 2 alone. The excellent photocatalytic performance of ReS 2 /CCN is mainly attributed to the efficient charge transport of highly crystalline CCN by eliminating deep defects, the strong visible light harvesting of ReS 2 nanoflakes, as well as the synergistic effect of an ultrathin layered 2D/2D heterojunction to rapidly enable charge-separation while inhibiting the charge recombination. This work provides an efficient photocatalyst for H 2 energy production, and sheds light on fundamental insight to a rational design of photo/electro nanocatalysts or heterojunction materials toward highly efficient photocatalyst. [ABSTRACT FROM AUTHOR]