Photobiocatalytic Solar Fuel and Solar Chemical Conversion: Sufficient Activity and Better Selectivity

Abstract

Converting renewable solar energy into fuel and value-added chemicals is a long-term objective of researchers and a promising solution for the energy crisis, environmental pollution, and global warming. Photosynthetic biohybrid systems (PBS) are receiving more and more attention, because they take advantage of both artificial semiconductor materials (high solar conversion efficiency) and living cells (high product selectivity) and, hence, enable the efficient capture and storage of solar energy in chemical bonds. In this perspective, we summarize findings on whole cell–semiconductor nanomaterial hybrid systems regarding solar driven H2 evolution, CO2 reduction, and N2 fixation in the past years. First, hydrogen yield and duration of different H2 evolution PBS are compared, and various assembly modes and electron transfer pathways are also introduced. Then, we evaluate the performance of CO2 reduction PBS based on the type of multicarbon products, as well as the challenges encountered by researchers and corresponding tentative solutions. Finally, we focus on photobiocatalytic N2 fixation, while introducing diverse N2 fixing microorganisms. Overall, obvious achievements have been made in photobiocatalytic solar fuel and solar chemical conversion in recent years, as innovative PBSs are constructed, molecular mechanisms are explored, and tentative solutions are proposed for scale-up, but huge challenges still exist. In the future, we should focus on revealing the interfacial electron transfer mechanisms and cellular energy allocation in order to significantly promote the solar-to-chemical conversion efficiency and meet the practical requirements.

Elucidating Electron Transfer Kinetics and Optimizing System Performance for Escherichia coli-Based Semi-Artificial H2 Production

“…Hence, various combinations of hydrogenases or molecular mimics with artificial photosystems have been widely studied. , Yet, these systems usually require costly enzyme purification, hindering industrial upscaling. This limitation has led to the more recent development of a variety of whole-cell-based biohybrid systems. ,− …”

“…10,19 Furthermore, different (sacrificial) electron donors are added to the system. Typical examples of such electron donors found in the literature are cysteine, 8,17,20 triethanolamine (TEOA), 9,19 bis-trismethane, 11 and ascorbic acid. 13,21 While a system consisting of a whole-cell biocatalyst, an artificial PS, and an electron donor is technically a complete photocatalytic system, many reports also include a mediator, e.g., methyl viologen 9 or reduced graphene oxide, 21 which facilitates the efficient transport of electrons from the photoactive system to the enzyme.…”

Nanoarchitecture Manipulation by Polycondensation on KCl Crystals toward Crystalline Lamellar Carbon Nitride for Efficient H2O2 Photoproduction

“…Thus, photocatalysis is deemed to be a potential method for the sustainable generation of H 2 O 2 . ,,,, The cost-effectiveness of the photocatalytic reaction process is, however, a barrier to its practical application. There are two critical factors for the cost-effectiveness: (1) low-cost photocatalysts with earth-abundant composition and (2) high efficiency of the photon-to-chemical conversion process. − Therefore, the main approach to the goal of sustainable H 2 O 2 production is the invention of an efficient and low-cost photocatalyst.…”

Artificial Photosynthesis of H2O2 by Synergistically Interplayed ZnIn2S4 and K+-Incorporated Polymeric Carbon Nitride

“…The application of H 2 O 2 -based AOP technology is, therefore, frequently restricted in some specific environment. On-site production of H 2 O 2 from O 2 and H 2 O with sustainable solar irradiation as the energy input is undoubtedly the most promising route for addressing the issues of energy crisis and environmental pollution. − However, solar conversion efficiency is the bottleneck to the real application of photocatalytic H 2 O 2 production, − due to the unfavorable recombination of the photoinduced charges. A plethora of photocatalysts have been developed for achieving high efficiency.…”