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

Area of Science:

• Biotechnology
• Materials Science
• Photocatalysis

Background:

• Sustainable solar-driven methanogenesis requires efficient integration of methanogens and semiconductors.
• Current systems often produce excess hydrogen (H₂) as a byproduct due to mismatched reaction rates.

Purpose of the Study:

• To develop a novel biotic-abiotic hybrid system for enhanced solar-driven methane (CH₄) production.
• To improve methane selectivity and efficiency by addressing the issue of excess H₂ generation.

Main Methods:

• Incorporation of binary metallic active sites (NiCu alloys) at the interface between cadmium sulfide (CdS) semiconductors and Methanosarcina barkeri.
• Fabrication of self-assembled Methanosarcina barkeri-NiCu@CdS hybrid material.
• Investigation of the role of NiCu alloys in facilitating hydrogen and electron transfer to methanogens.

Main Results:

• The Methanosarcina barkeri-NiCu@CdS system achieved nearly 100% CH₄ selectivity.
• A high quantum yield of 12.41 ± 0.16% was observed under light illumination.
• Ni-Cu-Cu hollow sites in NiCu alloys were found to directly supply hydrogen atoms and electrons to M. barkeri, supporting both extracellular and intracellular hydrogen cycles.
• This process effectively reduced H₂ production.

Conclusions:

• The engineered biotic-abiotic interface with NiCu alloys significantly enhances solar-driven methanogenesis efficiency and selectivity.
• The study provides crucial insights into optimizing hybrid systems for sustainable methane production.
• This approach offers a promising avenue for engineering advanced methanogenesis processes.