Solar-driven methanogenesis with ultrahigh selectivity by turning down H2 production at biotic-abiotic interface

Abstract

Integration of methanogens with semiconductors is an effective approach to sustainable solar-driven methanogenesis. However, the H2 production rate by semiconductors largely exceeds that of methanogen metabolism, resulting in abundant H2 as side product. Here, we report that binary metallic active sites (namely, NiCu alloys) are incorporated into the interface between CdS semiconductors and Methanosarcina barkeri. The self-assembled Methanosarcina barkeri-NiCu@CdS exhibits nearly 100% CH4 selectivity with a quantum yield of 12.41 ± 0.16% under light illumination, which not only exceeds the reported biotic-abiotic hybrid systems but also is superior to most photocatalytic systems. Further investigation reveal that the Ni-Cu-Cu hollow sites in NiCu alloys can directly supply hydrogen atoms and electrons through photocatalysis to the Methanosarcina barkeri for methanogenesis via both extracellular and intracellular hydrogen cycles, effectively turning down the H2 production. This work provides important insights into the biotic-abiotic hybrid interface, and offers an avenue for engineering the methanogenesis process.

Copolymerization synthesis of highly hydrophilic carbon nitride for efficient solar hydrogen production

“…4d, further suggesting that the photogenerated charge carriers were efficiently separated. 56,57 Moreover, both powder and solution of PCNInd 0.15 showed slight PL quenching than PCN, which also clearly suggested the efficient transfer of electrons (Fig. 4e).…”

Efficient Hydrogen Peroxide Photosynthesis over CdS/COF for Water Disinfection: The S-Scheme Pathway, Oxygen Adsorption, and Reactor Design

“…27 Among the various inorganic photocatalysts, cadmium sulfide (CdS) has been extensively investigated as an excellent n-type semiconductor, exhibiting favorable photochemical characteristics and remarkable high quantum efficiency when exposed to visible light. 30 Notably, the active depletion of h + in the valence band by the S-scheme heterojunction can be conducive to prevent the photocorrosion of CdS, thus avoiding the release of Cd 2+ ions. 31 By leveraging the suitable band-gap alignment, CdS holds great promise for constructing S-scheme heterostructures with selected covalent organic frameworks, facilitating the energetic photosynthesis of H 2 O 2 for water treatment.…”

Unassisted stimulation of autotrophic ethanol bioproduction by visible light

“…[19][20][21][22] In many of these systems, photoelectrochemical cells or particulate photocatalytic semiconductors are powering the autotrophic metabolism of acetogens with photoelectrons. [23][24][25][26][27][28][29][30] This is the case for illuminated C. autoethanogenum producing acetate from CO 2 with energy derived from nanoparticles of the semiconductor CdS displayed on its surface. 31 In all the reports on hybrid photosynthesis, acetogens are exposed to visible light, which is a known stress and/or stimulus impacting directly the metabolism and physiology of many nonphotosynthetic microbes.…”

“…19–22 In many of these systems, photoelectrochemical cells or particulate photocatalytic semiconductors are powering the autotrophic metabolism of acetogens with photoelectrons. 23–30 This is the case for illuminated C. autoethanogenum producing acetate from CO 2 with energy derived from nanoparticles of the semiconductor CdS displayed on its surface. 31…”