Bioinspired Metalation of the Metal-Organic Framework MIL-125-NH2 for Photocatalytic NADH Regeneration and Gas-Liquid-Solid Three-Phase Enzymatic CO2 Reduction.

Coenzyme NADH regeneration is crucial for sustained photoenzymatic catalysis of CO2 reduction. However, light-driven NADH regeneration still suffers from the low regeneration efficiency and requires the use of a homogeneous Rh complex. Herein, a Rh complex-based electron transfer unit was chemically attached onto the linker of the MIL-125-NH2 . The coupling between the light-harvesting iminopyridine unit and electron-transferring Rh-complex facilitated the photo-induced electron transfer for the NADH regeneration with the yield of 66.4 % in 60 mins for 5 cycles. The formate dehydrogenase was further deposited onto the hydrophobic layer of the membrane by a reverse filtering technique, which forms the gas-liquid-solid reaction interface around the enzyme site. It gave an enhanced formic acid yield of 9.5 mM in 24 hours coupled with the in situ regenerated NADH. The work could shed light on the construction of integrated inorganic-enzyme hybrid systems for artificial photosynthesis.

Graphitic Carbon Nitride Films: Emerging Paradigm for Versatile Applications.

Graphitic carbon nitride (g-C3N4) is a well-known two-dimensional conjugated polymer semiconductor that has been broadly applied in photocatalysis-related fields. However, further developments of g-C3N4, especially in device applications, have been constrained by the inherent limitations of its insoluble nature and particulate properties. Recent breakthroughs in fabrication methods of g-C3N4 films have led to innovative and inspiring applications in many fields. In this review, we first summarize the fabrication of continuous and thin films, either supported on substrates or as free-standing membranes. Then, the novel properties and application of g-C3N4 films are the focus of the current review. Finally, some underlying challenges and the future developments of g-C3N4 films are tentatively discussed. This review is expected to provide a comprehensive and timely summary of g-C3N4 film research to the wide audience in the field of conjugated polymer semiconductor-based materials.

Efficient and synergistic decolourization and nitrate removal using a single-chamber with a coupled biocathode-photoanode system.

With the continuous development of the chemical industries, synergistic removal of carbon and nitrogen contaminants has drawn much attention. In this work, a novel strategy for the synergistic removal of methyl orange (MO) and nitrate was developed in a single reactor by combining a TiO2/g-C3N4 nanosheet/graphene photoanode and denitrifying biofilm cathode. Under xenon light illumination, the photocatalytic MO decolorization rate exceeded 90% (the initial concentration of MO was as high as 100 mg·L-1) with a biocathode potential bias of -0.5 V vs Ag/AgCl; additionally, the decolourization rate apparently followed first-order kinetics with a constant of 0.11 ± 0.02 h-1. The improved MO decolourization rate was mainly because the biocathode effectively enhanced the charge separation of the photogenerated charge at the TiO2/g-C3N4 nanosheet/graphene photoanode interface. In the meantime, the effluent nitrate was lower than 1 mg·N·L-1 at a biocathode potential of -0.5 V vs Ag/AgCl. The results indicated that the coupled biocathode-photoanode system could serve the purpose of simultaneously degrading MO and accomplishing nitrate reduction. Considering the sustainability of sunlight and the use of a biocathode, the coupled biocathode-photoanode system is a promising alternative for the simultaneous removal of biorefractory organics and nitrate.

Construction of Thiazolo[5,4-d]thiazole-based Two-Dimensional Network for Efficient Photocatalytic CO2 Reduction.

The efficient conversion of CO2 to chemical fuels driven by solar energy is still a challenging research area in photosynthesis, in which the conversion efficiency greatly relies on photocatalytic coenzyme NADH regeneration. Herein, a photocatalyst/biocatalyst synergetic system based on a conjugated microporous polymer (CMP) was prepared for sustainable and highly selective photocatalytic reduction of CO2 to methanol. Two thiazolo[5,4-d]thiazole-linked CMPs (TZTZ-TA and TZTZ-TP) were designed and synthesized as photocatalysts. Slight skeleton modification led to a great difference in their photocatalytic performance. Triazine-based TZTZ-TA exhibited an unprecedentedly high NADH regeneration efficiency of 82.0% yield within 5 min. Furthermore, the in situ photocatalytic NADH regeneration system could integrate with three consecutive enzymes for efficient conversion of CO2 into methanol. This CMP-enzyme hybrid system provides a new avenue for accomplishing the liquid sunshine from CO2.

Synthesis and Composition-Dependent Visible Photocatalysis of Ag/AgBr Necklace-Like Heterostructures.

A two-step synthesis was developed to fabricate Ag/AgBr necklace-like nano-heterostructures at room temperature. Multiple crystalline Ag nanowires were used as templates following an oxidation route in situ from CuBr2 to create Ag/AgBr heterostructures. Polyvinylpyrrolidone can govern the formation of one-dimensional Ag/AgBr necklace-like nano-heterostructures. The composition of the heterostructures was adjusted by changing the amount of CuBr2 . Experimental conditions were optimized. In particular, the concentration and injection rate of copper bromide solution play an important role in controlling the oxidation of the Ag nanowires for the purpose of adjusting the morphology of the Ag/AgBr heterostructures. As a result, the heterostructures with 40 mol % AgBr displayed a regular necklace-like morphology. Under visible-light irradiation, Ag/AgBr necklace-like heterostructures with AgBr molar ratios of 10 to 50 % exhibited enhanced plasmonic photocatalytic performance for the degradation of organic pollutants (methyl orange, methylene blue, and rhodamine B).